Trending Topics pieces (Article Analyses, Evidence Clips and Other Topics) are published in timely response to recent media and journal articles, position statements, clinical guidelines, etc. Since they are based on the most recent evidence/publications, they may not be consistent with PEN evidence in other PEN content areas. As soon as possible, when this occurs, the PEN content will be reviewed and updated as needed.
Red and Processed Meat – It’s All About Interpretation
The International Agency for Research on Cancer (IARC) reported in 2015 that high processed meat or red meat diets are associated with higher relative risks of cancer, with stronger negative evidence for processed meats than red meat (1).
Johnston et al recently published a series of five systematic reviews in Annals of Internal Medicine that recommended that adults continue to consume red meat and processed meat at current levels of intake (2). These researchers considered three servings per week as a realistic reduction in meat consumption. Using meta-analyses to summarize the findings, they interpreted the data in two ways: they quantified how many per 1000 people would likely benefit from reducing red and processed meat consumption and then used Grading of Recommendations Assessment, Development and Evaluation (GRADE) tools (3,4) to translate these findings into recommendations.
Both the IARC and Johnston et al recognized limitations of the strengths of the evidence about red and processed meats (1,2). It was when Johnston et al interpreted their findings and made their recommendations that they differed from IARC’s conclusions. Johnston et al (1) used GRADE tools (4) to translate the findings into absolute risk differences and then make recommendations. GRADE instructs researchers when making recommendations to transparently consider the evidence concerning effects on health, as well as to consider values and preferences, costs, acceptability and feasibility of a recommendation. The GRADE methods have been endorsed by over 100 organizations including the World Health Organization and the Cochrane Collaboration (5).
Both groups looked at the body of evidence, which is observational study data. Regarding cancer, the IARC reported relative risks and statistical significance.
“Positive associations of colorectal cancer with consumption of processed meat were reported in 12 of the 18 cohort studies that provided relevant data, including studies in Europe, Japan, and the USA. Supporting evidence came from six of nine informative case-control studies. A meta-analysis of colorectal cancer in ten cohort studies reported a statistically significant dose–response relationship, with a 17% increased risk (95% CI 1•05–1•31) per 100 g per day of red meat and an 18% increase (95% CI 1•10–1•28) per 50 g per day of processed meat” (1).
Johnston et al translated their summary of the evidence into absolute risks of having a cardiometabolic or cancer outcome event:
“Although statistically significant, low- to very low-certainty evidence indicates that adherence to dietary patterns lower in red or processed meat is associated with a very small absolute risk reduction in 9 major cardiometabolic and cancer outcomes (range, 1 fewer to 18 fewer events per 1000 persons), with no statistically significant differences for 21 additional outcomes observed” (2).
The Johnston et al (2) group were divided when they voted about their recommendations to “continue current levels of red meat and processed meat consumption” (11 voted for the recommendation, three voted against it). They considered the following data for their recommendation:
- the low to very low certainty of evidence for the potential adverse health outcomes
- the very small absolute risk reduction based on three fewer servings of red or processed meat per week
- the small risk reductions combined with “peoples' attachment to their meat-based diet”, “is not likely to provide sufficient motivation to reduce consumption of red meat or processed meat”
- the large variability in peoples' values and preferences related to meat, and
- the panel focused exclusively on health outcomes associated with meat and did not consider animal welfare and environmental issues.
There is strong criticism of Johnson et al's paper. As an example, a press release from the Harvard T.H. Chan School of Public Health described the Johnston et al publication as “irresponsible and unethical to issue dietary guidelines that are tantamount to promoting meat consumption” (6).
Interpreting the Evidence
GRADE recommends looking beyond statistical significance to examine several quality of research indicators and the actual numerical strength of the effects. (See PEN®
eNews article - Why Using GRADE (to grade the evidence in PEN®) is Important to Practicing Dietitians
). The GRADE tools are intended to be used to evaluate the body of evidence about any health interventions for its strength, consistency, directness and precision for improving health and the individual studies for the risks of bias. (Refer to PEN®
eNews article, How PEN is ‘GRADE’ing the Evidence for You
for reasons why PEN is using GRADE methods). Essentially, both those who recommend continued meat consumption (2) and those who recommend decreased meat consumption (1,5) have made subjective assessments to judge the evidence and make their recommendations. Being transparent based on the GRADE methods, the new analysis (2) may be more substantiated, but as before, the evidence is not strong and decisions about eating or not eating meat comes down to individual preferences.
Many nutrition science recommendations are based on observational studies of what people eat and their subsequent health outcomes. A weakness of this approach is that people who eat healthy diets usually have higher incomes, do not smoke and practice other healthy lifestyles including more physical activity and a moderate alcohol intake. It is challenging, if not impossible, to disentangle these effects to be able to say that a healthy diet is the reason for better health outcomes.
There is no strong evidence to definitively support either the recommendations for continued red and processed meat consumption (2) or decreased meat consumption (1). The new analysis by Johnston et al (2) is based on the latest and endorsed methods (5) to summarize essentially the same evidence and to make recommendations. By using recommended methods, the new report (2) may be more substantiated. However, individual preferences and choices about eating meat are key to how we as dietitians work with clients.
The weaker the evidence, the more dietitians’ knowledge and professional training matter to interpret and to provide nutrition guidance. We need to continue to respect people’s values and preferences as well as to encourage a variety of foods in moderation and to make wise and informed choices to meet nutrition needs. Those who avoid or decrease their meat consumption for health, environmental and/or animal welfare reasons may need assistance obtaining sufficient protein, iron, zinc and vitamin B12. Those who avoid dairy products, may need assistance obtaining sufficient protein and calcium, especially children (7). People who eat generous quantities of meat may need assistance to ensure their diet contains sufficient vegetables, fruit, calcium and fibre.
Most diets would likely be improved with the inclusion of some plant-based proteins including some beans, lentils and nuts for their fibre, low glycemic index and nutrient contributions. Recommended nutrient intakes for protein (8) and current country dietary guidelines should continue to be followed. See Additional Content: International Healthy Eating Guideline Collection.
- Bouvard V, Loomis D, Guyton KZ, Grosse Y, Chissassi FE, Benbrahim-Tallaa L, et al. Carcinogenicity of consumption of red and processed meat. Lancet Oncol. 2015 Dec;16(16):1599-600. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/26514947
- Johnston BC, Zeraatkar D, Han MA, Vernooij RWN, Dib EL, Marshall C, et al. Unprocessed red meat and processed meat consumption: dietary guideline recommendations (NutriRECS) Consortium. Ann Intern Med. 2019 Oct. doi:10 .7326/M19-1621. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31569235
- Guyatt GH, Oxman AD, Akl EA, Kunz R, Vist G, Brozek J, et al. GRADE guideline: 1. Introduction – GRADE evidence profiles and summary of findings tables. J Clin Epidemiol. 2011 Apr;64(4):383-94. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/21195583
- Schünemann H, Brożek J, Guyatt G and Andrew Oxman A, Eds. Handbook for grading the quality of evidence and the strength of recommendations using the GRADE approach. 2013. Available from: https://gdt.gradepro.org/app/handbook/handbook.html
- GRADE. GRADE working group. [cited 2019 Oct 2]. Available from: http://www.gradeworkinggroup.org/
- Harvard T.H. Chan School of Public Health. New “guidelines” say continue red meat consumption habits, but recommendations contradict evidence. The Nutrition Source. 2019 Sep 30. Available from: https://www.hsph.harvard.edu/nutritionsource/2019/09/30/flawed-guidelines-red-processed-meat/
- The National Academies Press. Dietary Reference Intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. 2005. Available from: https://www.nap.edu/read/10490/chapter/12
Twelve Country Comparison of Packaged Food and Beverages Using Health Star Rating System
The Health Star Rating (HSR) system was used to compare 394,815 packaged foods and beverages available in 12 countries (1). This study identified encouraging and concerning results. Encouraging for residents of Britain, Australia, Canada and the U.S is that these countries' packaged foods ranked the highest for their overall nutrient profiles, while the foods in India, Hong Kong, China and Chile ranked the lowest. The authors suggested that the differences between high and low-middle income countries may be due to the lack of food labelling in low-middle income countries or an inability to implement and enforce healthy food policies. As well, there could be a demand by consumers in high income countries for healthier foods and more actions from the food industry to produce healthier products. However, not all of the high ranking countries had consistent ratings across all nutrients. Perhaps the most concerning for Canadians was that packaged foods in the “US and Canada had the highest mean sodium content of all 12 countries examined”.
There are limits to nutrient profiling systems that should be kept in mind. No food rating system is perfect. The HSR is based on nutrients in the foods per 100 g or 100 mL, an evaluation method that rates some foods more or less favourably than systems that evaluate foods per 100 kilocalories or in usual serving sizes (2,3). In studies, nutrient profiling systems based on 100 kcal and serving sizes perform better than those based on 100 g, such as the HSR (4). For example, foods that are consumed in low quantities, such as cheese, are rated poorly by the HSR system for the saturated fat and sodium contents when assessed per 100 grams, while cheese is likely seldom consumed in 50-100 g servings (2,5). In contrast, foods that are consumed in large quantities, such as soup and juices, have their sodium and sugars contents assessed in unrealistically low serving sizes of 100 mL. The same problem happens with the desirable nutrients when assessed per 100 g, but in the opposite direction. Almonds are sometimes quoted as a source of calcium, as they have 247 mg/100 g (6). However, at 587 kcal/100 g, almonds may not be a very good source of calcium/day for many people. In comparison 1 and 2% milk and calcium-fortified soy beverages have 34 to 52 kcal/100 g and supply 234 to 374 mg of calcium per 100 kcal.
Another observation of the HSR is that it considers total sugars and does not discriminate between innate sugars versus added sugars, which lowers the ratings of some foods such as unsweetened fruit (7). Other factors that the HSR system does not consider are foods’ affordability (8), and the amount of processing the food has undergone (4).
While classifying foods by their nutrients does not address all aspects of a healthy diet, when used along with other interventions, nutrient profiling systems may help to improve the dietary intake of consumers (9). The authors of this study concluded that nutrient profiling systems are important for the development and monitoring of healthy food policies and products (1).
For information on the effects of food labelling systems, nutrition panels and menus on consumer behaviour see the PEN Food and Nutrition Labelling Knowledge Pathway.
- Dunford EK, Ni Mhurchu C, Huang L, Vandevijvere S, Swinburn B, Pravst I, et al. A comparison of the healthiness of packaged foods and beverages from 12 countries using the Health Star Rating nutrient profiling system, 2013-2018. Obes. Rev. 2019 Jul 22. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31328385
- Dickie S, Woods JL, Lawrence M. Analysing the use of the Australian Health Star Rating system by level of food processing. Int J Behav Nutr Phys Act. 2018 Dec 13;15(1):128 Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30545373
- Drewnowski A. Nutrient density: addressing the challenge of obesity. Br J Nutr. 2018 Aug;120(s1):S8-14. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29081311
- Drewnowski A, Fulgoni VL 3rd. Nutrient density: principles and evaluation tools. Am J Clin Nutr. 2014 May;99(5 Suppl):1223S-8S. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/24646818
- Mhurchu CN, Eyles H, Choi YH. Effects of a voluntary front-of-pack nutrition labelling system on packaged food reformulation: the Health Star Rating System in New Zealand. Nutrient. 2017 Aug 22;9(8). Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/28829380
- Government of Canada. Canadian Nutrient File (CNF) – Search by Food. 2018 Feb 6. Available from: https://food-nutrition.canada.ca/cnf-fce/index-eng.jsp
- Menday H, Neal B, Wu JHY, Crino M, Baines S, Petersen KS. Use of added sugars instead of total sugars may improve the capacity of the Health Star Rating System to discriminate between core and discretionary foods. J Acad Nutr Diet. 2017 Dec;117(12):1921-30.e.11. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29173348
- Cooper SL, Pelly FE, Lowe JB. Assessment of the construct validity of the Australian Health Star Rating: a nutrient profiling diagnostic accuracy study. Eur J Clin Nutr. 2017 Nov;71(11):1353-9. Abstract available from: https://www.ncbi.nlm.gov/pubmed/28294168
- World Health Organization. Nutrient Profiling. [cited 2019 Sep 3]. Available from: https://www.who.int/nutrition/topics/profiling/en/
The Science and Politics of Nutrition Series - Dietary Carbohydrates: Role of Quality and Quantity in Chronic Disease
The British Medical Journal (BMJ) launched a series of open-access, peer-reviewed articles under the title, Food for Thought - The Science and Politics of Nutrition. The series covers a variety of controversial nutrition topics where there are uncertainties in the evidence and debate among experts. The articles aim to bring together a wide range of viewpoints and to discuss the areas of consensus and uncertainty as well as how to move forward with research, policy and guidelines for practitioners.
This featured article in the series provides background information on the role of carbohydrate consumption in human development, the relation between carbohydrate types (chain length, glycemic index and load, fibre and resistant starch, added and free sugar and composite quality indices) and health outcomes, and a narrative overview of how carbohydrates containing foods (grains, potatoes, legumes and fruit) affect health (reviewing salivary amylase) (1). The article is not a systematic review, so needs to be considered a narrative review, in which the authors’ opinions are considered.
The key messages in the article:
- “Human populations have thrived on diets with widely varying carbohydrate content
- Carbohydrate quality has a major influence on risk for numerous chronic diseases
- Replacing processed carbohydrates with unprocessed carbohydrates or healthy fats would greatly benefit public health
- The benefit of replacing fructose containing sugars with other processed carbohydrates is unclear
- People with severe insulin resistance or diabetes may benefit from reduction of total carbohydrate intake” (1).
Additional PEN Content
Upcoming PEN Content
Are diets higher in total dietary fibre (including whole grains, cereals, vegetable, fruit, and legume fibre) recommended to decrease the risk of cardiovascular disease (CVD)?
This practice question is based on a high quality systematic review:
Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2;393(10170):434-45. doi: 10.1016/S0140-6736(18)31809-9. Epub 2019 Jan 10. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30638909
- Ludwig DS, Hu FB, Tappy L, Brand-Miller J. Dietary carbohydrates: role of quality and quantity in chronic disease. BMJ. 2018 Jun 13;361:k2340. doi: 10.1136/bmj.k2340. Citation available from: https://www.ncbi.nlm.nih.gov/pubmed/29898880
Animal and Plant-based Protein Foods Effects on Blood Lipid Levels
A recent randomized control trial of atherogenic lipid levels was reported in the American Journal of Clinical Nutrition (1). Participants were randomly assigned to either high (∼14% total energy) or low (∼7% total energy) saturated fat (SFA). Within each of these arms participants were further randomized to various sources of protein (red meat, white poultry meat, plant-based protein (legumes, nuts, grains, isoflavone-free soy products)) and tested in a factorial crossover design. This design was used to test both the effects of different levels of saturated fat and the various protein sources. The leanest cuts of red and white meat were used with all visible fat and poultry skin removed. All food (standardized entrées, side dishes, caloric beverages, snacks) was provided (except for fruit and vegetables, to ensure freshness) to the participants. Diet energy was individualized to ensure weight maintenance. The higher SFA was mostly from butter and full-fat dairy products, replaced with monounsaturated fats in the lower SFA arms. Participants, aged 21-65 years, were of good health; 113 of the 177 enrolled (63%) completed the study. Diets were consumed for four weeks with a two to seven-week washout period in between. Primary outcomes were LDL cholesterol, apoB, small plus medium LDL and the total/HDL cholesterol ratio.
Results and Conclusions
The trial revealed that, independent of SFA content, low density lipoprotein (LDL) cholesterol and apoB were higher with white and red meat than with plant-based protein (P<0.0005 for all) (1). Total/high density lipoprotein and small plus medium LDL cholesterol were not affected by protein source (P=0.51 and P=0.10). There were no significant differences between red and white meat on other primary outcomes. Furthermore, high SFA intakes increased LDL cholesterol (P=0.0004, apoB (P=0.0002) and large LDL (P=0.0002) compared with low SFA, independent of protein source.
The authors concluded that their findings support current guidelines of promoting increased consumption of plant-based foods for reducing CVD risk (1). The study was not able to conclude that choosing lean white meat offered advantages over lean red meat for reducing CVD risk.
PEN Evidence Analyst Analysis
The strengths of this study include:
- It was a randomized trial (with concealed allocation using numbered envelopes so the researchers would not be aware of the next randomization sequence.
- It was a cross-over design (participants were their own controls).
- Participants were provided with the food.
This study avoided confounding by three of the elements of the design. First by randomization to the order of the diets, second by using the participants as their own controls, and third by providing most of the food to the participants, to avoid confounding by other dietary factors.
A limitation of this study is that it does not refer to higher fat meats since blood lipid effects were only examined after the consumption of only very lean meats. A second limitation is the indirectness of the blood levels, which may not directly predict cardiovascular disease.
For additional interpretation of the study, see: https://theconversation.com/research-check-is-white-meat-as-bad-for-your-cholesterol-levels-as-red-meat-118390.
- Bergeron N, Chiu S, Williams PT, M King S, Krauss RM. Effects of red meat, white meat, and nonmeat protein sources on atherogenic lipoprotein measures in the context of low compared with high saturated fat intake: a randomized controlled trial. Am J Clin Nutr. 2019 Jun 4. pii: nqz035. doi: 10.1093/ajcn/nqz035. [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31161217
Ultra-processed Foods and Early Death
Researchers continue to explore the relationship between the foods we eat and health outcomes. The British Medical Journal (BMJ) recently published two articles on the health effects associated with the consumption of ultra-processed foods and early death:
The National Health Service (NHS) in the U.K. has provided this analysis of the research, which notes the challenges of cohort studies, including the inability to prove cause and effect, the importance of potential confounding factors with observational research, and the difficulty of defining ultra-processed foods. People who frequently eat ulta-processed foods are different in several ways including income, physical activity and smoking habits, from people who eat foods prepared from scratch (1); it is not possible in studies such as these to fully control for these differences. Thus, it is cannot be assumed that the ultra-processed foods actually caused the cardiovascular disease or early deaths or that other aspects of their lifestyle were more important.
In addition, see the February 2019 PEN Trending Topic: The Association Between Ultraprocessed Food Consumption and the Risk of Mortality – What is the Real Deal?
- Schnabel L, Kesse-Guyot E, Allès B, Touvier M, Srour B, Hercberg S, et al. Association between ultraprocessed food consumption and risk of mortality among middle-aged adults in France. JAMA Intern Med. 2019 Feb 11. doi:10.1001/jamainternmed.2018.7289. [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30742202
The Association Between Ultraprocessed Food Consumption and the Risk of Mortality – What is the Real Deal?
Originally Posted February 15, 2019. Reposted June 5, 2019
Another observational nutrition study is making headlines around the world (1-3) but is also raising concerns about the failure of news stories to address the significant limitations of the study. The observational prospective cohort study looked at the association between ultraprocessed food consumption and the risk of mortality in middle-aged adults in France (4). The authors concluded that an association existed based on the data of more than 44,000 participants.
A PEN Evidence Analyst offered this analysis:
The results portray a very weak relationship between ultraprocessed foods and mortality. The effect size, which was equal to a hazard ratio of 1.14, is so small that it is not likely of importance. GRADE guidelines encourage that for an observational study an effect size should be greater than 2, or better yet 5, before we should assume that there is an important effect (5). This hazard ratio of 1.14 was statistically significant, which is not surprising because there were over 44,000 participants in the study. When the sample size is very large, statistical significance is highly likely even when the effect is so small that it is not likely of any real importance.
Additional concerns are that the categorization of foods in the ultraprocessed category included sugar-sweetened beverages and highly processed snack foods but also included ready-made meals and breads, which could be quite nutritious. Further, the researchers allowed the participants to select which 24-hour periods they reported their food intake, so we don’t know how well their selections reflect typical intakes.
The results observed could be due to the fact that those that ate the most of these ultraprocessed foods were those most likely to have higher mortality rates for reasons beyond dietary intake. The individuals consuming the most of these ultraprocessed foods were more likely to be of lower income, smoke and/or be single obese males with low levels of physical activity. Some additional variable or variables related to these variables that were controlled for in the analysis could be the actual causal factor for mortality. Therefore, residual confounding may explain this study’s results.
The researchers did mention that reverse causation was possible; that is those people who are at higher risk of death from a chronic disease may have been selecting more processed foods. This type of study design cannot rule out reverse causation.
The NHS and Science Media Centre reviews also outline the limitations and put the study and its findings into perspective.
- Scutti S. Eating 'ultraprocessed' foods accelerates your risk of early death, study says. CNN. 2019 Feb 12. Available from: https://edition.cnn.com/2019/02/11/health/ultraprocessed-foods-early-death-study/index.html
- Eating ultra-processed foods can increase risk of early death: study. CTV. 2019 Feb 12. Available from: https://www.ctvnews.ca/health/eating-ultra-processed-foods-can-increase-risk-of-early-death-study-1.4293071
- Donnelly L. Modern diets could be killing us, suggests major study on ultra-processed foods. The Telegraph News. 2019 Feb 11. Available from: https://www.telegraph.co.uk/news/2019/02/11/modern-diets-could-killing-us-suggests-major-study-ultra-processed/
- Schnabel L, Kesse-Guyot E, Allès B, Touvier M, Srour B, Hercberg S, et al. Association between ultraprocessed food consumption and risk of mortality among middle-aged adults in France. JAMA Intern Med. 2019 Feb 11. doi:10.1001/jamainternmed.2018.7289. [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30742202
- Guyatt GH, Oxman AD, Sultan S, Glasziou P, Akl EA, Alonso-Coello P, et al. GRADE guidelines: 9. Rating up the quality of evidence. J Clin Epidemiol. 2011 Dec;64(12):1311-6. doi: 10.1016/j.jclinepi.2011.06.004. Epub 2011 Jul 30. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/?term=21802902
New Guidelines on the Risk Reduction of Cognitive Decline and Dementia
The World Health Organization (WHO) has released new evidence-based guidelines, Risk Reduction of Cognitive Decline and Dementia, developed using the GRADE process. The nutrition section includes conditional recommendations for the Mediterranean diet and a healthy, balanced diet to reduce the risk of cognitive decline and/or dementia; and a strong recommendation not to use supplemental polyunsaturated fatty acids, vitamins B and E and/or a multi-complex supplement for reducing the risk of cognitive decline and/or dementia.
The release of these guidelines is timely as the PEN Team is in the early stages of updating the Mental Health - Dementia Knowledge Pathway. Watch for updates in the near future.
Medically-Tailored Home Meal Program Associated with Reduced Inpatient Admissions and Health Care Costs
“Is participating in a medically tailored meal delivery program for medically and socially complex adults associated with fewer inpatient admissions?” (1). The cohort study published in JAMA examining this question looked at weekly home delivery of 10 free ready-to-eat medically-tailored meals (MTMs) (median duration of MTMs was nine months) to 499 individuals who were independently living and had a medical condition (such as heart disease or diabetes). A registered dietitian determined the appropriate diet and meals based on the individual’s health condition(s) as identified by the referring health provider. The authors compared health care use/inpatient admissions (primary data), admission to a skilled nursing facility and health care costs (secondary outcomes) with 521 non-meal recipients who were matched to the recipients (mean [SD] age, 52.7 [14.5] years; 568 [55.7%] female) based on demographics, disease states and neighborhood characteristics. The authors found that those who received MTMs were less likely to have hospital and skilled nursing facility admissions resulting in less overall health care costs.
See this commentary, Food Is Medicine—The Promise and Challenges of Integrating Food and Nutrition Into Health Care, for more information on the study and its results.
- Berkowitz SA, Terranova J, Randall L, Cranston K, Hsu J. Association between receipt of a medically tailored meal program and health care use. JAMA. 2019 Apr. doi: 10.1001/jamainternmed.2019.0198. [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31009050
Warning Against Eating Human Placenta
A Canadian Television Network (CTV) news posting writes, “A group of Canadian gynecologists is urging people not to eat the human placenta. A recommendation from the Society of Obstetricians and Gynaecologists of Canada, recently published in the Journal of Obstetrics and Gynaecology Canada, indicates there is no evidence of a health benefit from the practice known as placentophagy and there [is] a potential for serious harm”.
See Additional Information:
Report Card on Access to Obesity Treatment for Adults in Canada
Obesity Canada has just released an updated 2019 report card on access to obesity treatments for adults in Canada. The report focuses on four key obesity management tools:
- specialists and interdisciplinary teams for behavioural intervention
- medically supervised weight-management programs with meal replacements
- anti-obesity medications
- bariatric surgery (1).
Major findings indicate that since the 2017 report there have been:
- no improvements in treatment
- obesity is still regarded as self-inflicted
- there are a lack of interdisciplinary teams to treat patients
- patients cover their own costs for weight management programs and foods
- obesity drugs are not covered in public programs
- there are no policies or guidelines to treat or manage obesity in Canada
- there are long wait times for bariatric surgery (1).
Five key recommendations are provided as follows:
- “Governments, employers and the health insurance industry should officially adopt the position of the Canadian Medical Association that obesity is a chronic disease and orient their approach/resources accordingly.
- Governments should recognize that weight bias and stigma are barriers to helping people with obesity and enshrine rights in provincial/territorial human rights codes, workplace regulations, healthcare systems and education.
- Governments should include anti-obesity medications, weight-management programs with meal replacement and other evidence-based products and programs in their provincial drug benefit plans.
- Employers should recognize and respond to obesity as a chronic disease and provide coverage for evidence-based obesity programs and Health Canada approved treatments for their employees through health benefit plans.
- Governments and health authorities should increase the availability of interdisciplinary teams and increase their capacity to provide evidence-based obesity management.”(1).
The PEN® Team will be reviewing the included evidence as it relates to existing content.
- Obesity Canada-Obésité Canada. Report Card on Access to Obesity Treatment for Adults in Canada 2019. April 2019. Available from: http://obesitycanada.ca/wp-content/uploads/2019/04/OC-Report-Card-2019-Eng-F-web.pdf
Red Meat, Comparison Diets and CVD
A new meta-analysis of random control studies looked at the effects of red meat consumption and risk factors for cardiovascular disease (blood lipids, apolipoproteins, blood pressure) (1). The meta-analysis involved 1,803 participants from 36 RCTs that compared red meat diets with diets that replaced red meat with a variety of foods. The study found that the results depended on the composition of the comparison diet: there were improvements in blood lipids when red meat was substituted with high quality plant protein sources but not when replaced with low quality carbohydrates. The senior author of the study, Meir Stampfer, stated: “Asking 'Is red meat good or bad?' is useless,"…. "It has to be 'Compared to what?' If you replace burgers with cookies or fries, you don't get healthier. But if you replace red meat with healthy plant protein sources, like nuts and beans, you get a health benefit" (1).
PEN Team Comment:
This study combined the results from 36 randomized controlled trials. Randomized controlled trials can give more certainty of the findings. If the trials were well-designed and conducted, the intervention and control groups should be similar, providing confidence that any differences in outcome were due to the intervention compared to the comparison group. The confidence intervals from the individual studies (seen as the horizontal lines for each study in the Figures) were wide, indicating variability in the results and/or small sample sizes.
In addition, this study identified one of the difficulties of nutrition trials: “Inconsistencies regarding the effects of red meat on cardiovascular disease risk factors are attributable, in part, to the composition of the comparison diet” (2).
- ScienceDaily. Substituting healthy plant proteins for red meat lowers risk for heart disease. 2019 Apr 9. Available from: https://www.sciencedaily.com/releases/2019/04/190409141808.htm
- Guasch-Ferre M, Satija A, Blondin SA, Janiszewski M, Emlen E, O’Connor LE, et al. Meta-analysis of randomized controlled trials of red meat consumption in comparison with various comparison diets or cardiovascular risk factors. Circulation. 2019 Apr 9;139(15):1828-45. doi:10.1161/CIRCULATIONAHA.118.035225. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30958719
Is Diet Associated with Death Rates Across the Globe?
A study published in the Lancet of the global burden of disease tracked consumption trends of 15 dietary factors between 1990 and 2017 in 195 countries. The study looked at major food groups, some nutrients and examined the associations between diet and death and disability-adjusted life-years from non-communicable diseases (e.g. diabetes, cardiovascular disease, cancer). Dietary elements examined included estimated intakes of fruit, vegetables, legumes, whole grains, nuts and seeds, milk, fibre, calcium, seafood omega-3 fatty acids, polyunsaturated fats, red meat, processed meat, sugar-sweetened beverages, trans fatty acids and sodium.
The authors observed that diets low in whole grains and fruit, and high in sodium were associated with more than half of all diet-related global deaths. In North America, the data suggested that the largest dietary contributor to death was from the low intake of whole grains. For more reading about the study and a discussion of some the limitations, see the Science News article Globally, One in Five Deaths are Associated with Poor Diets.
This study is an ecologic study, since the researchers analyzed country-specific data rather than individuals’ data (1,2). They did not know whether the people who died were the people with inferior diets, rather they assumed that the diet information represented everyone in the country (1). The study primarily used dietary intake data prepared by others, usually 24-hour recall data for dietary estimates. There were likely differences in how diets were measured in the various countries. Twenty-four-hour recall data is likely to vary in quality and may not provide strong representations of participants diets (3).
The researchers adjusted the country mortality rates for differences in age and sex distributions in the countries (1). There were no considerations for smoking, physical activity, weight status, other lifestyle variables or inequality in the countries. The analysis assumed that everyone in the countries consumed the average diet of those studied in each country. The results stratified by socioeconomic status (SES), showed weaker relationships between diet and mortality for people with the highest and lowest SES. These findings suggest that other factors, such as social determinants of health, which influence economic conditions, lifestyle, smoking etc., are likely more influential (positively for high SES and negatively for low SES) making diet relatively less influential on mortality at the extremes of SES.
This study has a positive focus on foods that may improve health outcomes. Caution is needed in interpreting this ecologic studies’ results since interpretations could be considered an “ecological fallacy”, especially if these findings are used to assume that the noted association exists for individuals and that if individuals make these dietary changes it would decrease their risk of death (2).
- GBD 2017 Diet Collaborators. Health effects of dietary risks in 195 countries, 1990-2017: a systematic analysis for the Global Burden of Disease study 2017. The Lancet. Published online 2019 Apr 3. Available from DOI: http://dx.doi.org/10.1016/S0140-6736(19)30041-8
- Barratt B, Kirwan M 2009, Shantikumar S 2018. The design, applications, strengths and weaknesses of descriptive studies and ecological studies. HealthKnowledge. Education, CPD and Revalidation from PHAST. 1a-Epidemiology. 2018. [cited 2019 Apr 7]. Available from: https://www.healthknowledge.org.uk/public-health-textbook/research-methods/1a-epidemiology/descriptive-studies-ecological-studies
- Amoutzopoulos B, Steer T, Roberts C, Cade JE, Boushey CJ, Collins CE, et al. Traditional methods v. new technologies – dilemmas for dietary assessment in large-scale nutrition surveys and studies: a report following an international panel discussion at the 9th
International Conference on Diet and Activity Methods (ICDAM9), Brisbane, 3
September 2015. J Nutr Sci. 2018 Apr 2;7e:11.
DOI: 10.1017/jns.2018.4. eCollection 2018. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/?term=29686860
Gut Microbiota in Nutrition and Health
This article, on the role of the gut microbiota in nutrition and health, is another in the BMJ series of open access, peer-reviewed articles examining controversial nutrition topics where there are uncertainties in the evidence and debate among experts. References
Most of the human studies of the gut microbiota and its associations with disease conditions are case control observational studies, conducted at one point in time (1). It is not possible from these studies to know whether the patterns of microbiota caused the disease or whether the disease, its treatment or some related factor caused the microbiota pattern. Animal studies of some topics are suggestive of a causal relationship, but the mechanisms might be different in animals versus humans (1). Future longitudinal and randomized trials will help to understand these relationships.
This BMJ article describes the gut microbiota and its associations with health, the influence of diet and medication on the microbiota, and how the gut microbiota can be manipulated by diet, probiotics and dietary fibre. It summarizes the current state of understanding of this complex topic, describing what is known from human randomized trials and animal studies and current areas yet to be clarified.
Looking for more information? See the Additional PEN Content:
- Valdes AM, Walter J, Segal E, Spector TD. Role of the gut microbiota in nutrition and health. BMJ. 2018 Jun 13;361:k2179. doi: 10.1136/bmj.k2179. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29899036
Another Study on Cholesterol, Eggs and CVD Risk
A recent study by Zhong, et al. published in JAMA has been cited in the press including MedicalNewsToday on March 15, 2019. The study analyzed pool data from six prospective studies covering a period up to 31 years (median 17 years follow up) and involving 29,615 men and women in the U.S. It reviewed self-reported intake of cholesterol-containing foods, including eggs, and identified a positive association with an increased risk of cardiovascular disease (CVD) and deaths from other causes.
Here are two analyses of the study:
Note that this was not a systematic review and the findings are not consistent with systematic reviews and meta-analyses of other cohort studies. For more information and practice recommendations, see PEN Practice Question: Are interventions to decrease dietary cholesterol intake (e.g. restricting eggs) recommended for the primary prevention of cardiovascular disease (CVD)?
DRI Updates for Sodium and Potassium
A press release from the National Academies of Sciences, Engineering, and Medicine outlines a new report titled, Dietary Reference Intakes for Sodium and Potassium. A National Academies committee conducted the study to assess current relevant data and update, as appropriate, the DRIs for sodium and potassium that were developed in 2005. Posted: 2019-03-11
The report “reaffirms the sodium AI for individuals ages 14-50, decreases the sodium AIs for children age 1-13, increases the sodium AIs for adults ages 51 and older, and decreases the potassium AIs for individuals age 1 and older” (1). In addition, the committee applied recommendations from the 2017 Guiding Principles Report and established a new category of DRIs based on chronic disease, the Chronic Disease Risk Reduction Intake (CDRR) for sodium, based on the benefits of reducing sodium intake on blood pressure and cardiovascular disease risk.
The review was sponsored by Health Canada, the U.S. National Institutes of Health, the Public Health Agency of Canada, the U.S. Centers for Disease Control and Prevention, the U.S. Department of Agriculture, and the U.S. Food and Drug Administration.
Also available is a Consensus Study Report providing report highlights.
National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for sodium and potassium. Washington D.C.: The National Academies Press; 2019. Available from: https://www.nap.edu/read/25353/chapter/1#ii
Arsenic in Rice Products for Children
A recent CBC Marketplace program reported on the testing of the levels of arsenic in rice cereals and snacks for infants and children. For an in-depth examination and analysis of the evidence on the topic of arsenic in the diets of infants and children, see the 2018 PEN Trending Topic: Do New Parents or Parent-to-be Need to be Concerned About Dietary Arsenic Exposure?. For further information on rice and arsenic, see: PEN's Food Safety - Arsenic in Rice Background.
The Bottom Line
Limit or avoid giving infants and young children cereals made from brown rice flour and products with brown rice syrup, since they have more arsenic. Some rice is okay for young children, but it is best to give infants and children a variety of grains and use infant rice cereals and rice-based products, such as wafers and crackers, in moderation.
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