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.
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.
The Association Between Ultraprocessed Food Consumption and the Risk of Mortality – What is the Real Deal?
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
Trending Topic - Why Are Journal Article Retractions Important to Practitioners?
The New Canada’s Food Guide is Released!
Nathalie Savoie, CEO of Dietitians of Canada, attended the launch of Canada’s new Food Guide in Montreal today. The updated food guide, shown as a plate model, provides information on food choices, eating habits, recipes, tips and provides a suite of resources for consumers and professionals. The emphasis is on plant-based foods and their health and environmental benefits. The guide focuses equally on WHAT and HOW to eat and no longer suggests portion sizes.
For additional content see:
The "Planetary Health Diet" – What’s it All About?
A report was launched on January 17, 2019 by The EAT- Lancet Commission on Food, Planet, Health that presents “a global planetary health diet that is healthy for both people and planet” (1). (Note: to download the complete report you must log into your Lancet account or complete the free registration to the Lancet website). EAT is “a global, non-profit start-up dedicated to transforming our global food system through sound science, impatient disruption and novel partnerships” (2).
The EAT-Lancet Commission brought together “37 experts from 16 countries in various fields of human health, agriculture, political sciences and environmental sustainability to develop global scientific targets for healthy diets from sustainable food production” (3). With the population set to reach 10 billion people by 2050, researchers stressed the link between what we eat and human and planetary health. Future food production must be intensified in regards to sustainability to meet the needs of the growing population within the planetary limits for climate change, biodiversity loss, land and water use, as well as nitrogen and phosphorous cycles (1).
In this important report, authorities have attempted to look at “nutrition, health impacts, ecosystems and feasibility with culture” and provide strategic and practical information for policy development. It is basically calling for a transformation of the food we eat and ”getting it right with food will be an important way for countries to achieve the targets of the UN Sustainable Development Goals and the Paris Agreement on climate change” (1).
“Ensuring that all certified health professionals have a demonstrable level of competence surrounding planetary health diets”, the EAT-Lancet Commission prepared a brief for professionals (3): with information about what they should know and what they should do to contribute to the “Great Food Transformation” (1).
An overview of the diet recommendations include reducing the consumption of animal protein so that proteins should be from plant sources as much as possible and reducing the consumption of ultra-processed foods and added sugar. While this is nothing new, as we have been hearing these recommendations for years, what is new is the more specific guidelines for food group consumption (1,3):
The whole grains portions are adjusted to meet energy targets. In addition, the diet has room for 31 g of sugar and about 50 g worth of oils, such as olive oil, and no dairy fats such as butter.
- Nuts (peanuts and tree nuts) - 50 g a day
- Beans, Chickpeas, Lentils and Other Legumes (dried) - 50 g a day
- Soy Foods (dry) - 25 grams a day
- Fish - 28 g a day
- Eggs - 13 g a day (about 1.5 eggs per week)
- Meat and Poultry - 14 g a day of red meat and 29 g a day of poultry
- Dairy and Dairy Products (including cheese) - 250 g a day (the equivalent of one glass of milk)
- Carbs - Whole grains including rice, wheat and corn (dry) - 232 g a day and 50 g a day of starchy vegetables
- Vegetables and Fruit - vegetables (300 g) and fruit (200 g) a day.
For Additional Content:
- Willet W, Rockström J, Loken B, Springmann M, Lang T, Vermeulen S, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. 2019 Jan 16. pii: S0140-6736(18)31788-4. doi: 10.1016/S0140-6736(18)31788-4. Citation available from: https://www.ncbi.nlm.nih.gov/pubmed/30660336
- EAT Forum – About EAT. [cited 2019 Jan 21]. Available from: https://eatforum.org/about/
- EAT- Lancet Commission. Brief for healthcare professionals. January 2019. Available from: https://eatforum.org/content/uploads/2019/01/EAT_brief_healthcare-professionals.pdf
The Law of Food Allergy and Accommodation in Canadian Schools
A recent article examined how current laws in Canada can guide future school policies to accommodate allergies, food bans and disabilities in children. See additional resources from the School Health Knowledge Pathway Related Tools and Resources along with these country-specific guidelines:
Food Trends for 2019
It's January, and there are many food trend predictions for the year. Real food, mindful eating and drinking are the top trends according to Global News. Other common themes include challenges because of increasing food prices; continued emphasis on a plant-based diet, eating for health and reducing food waste for sustainability; and ethnic food specialties. Check out the following predictions from around the globe:
Further Commentary on the PURE Study: Dairy Intake, Cardiovascular Disease and Mortality
An editorial by Louie and Rangan discusses the findings from the Prospective Urban Rural Epidemiology (PURE) study on the association of total and individual types of dairy food intake with major cardiovascular disease events and mortality (1). The editorial authors report that the PURE study found that higher daily consumption of dairy products may be protective and that the associations were stronger for whole fat dairy foods in low and middle income countries with lower mean dairy intakes (i.e. South and Southeast Asia, Africa and China).
Louie and Rangan point out that while this current analysis is not as affected by the study design issues of other PURE study results, there were large limitations; the most notable being that dietary intakes were only assessed at the beginning of the study (1). A single assessment of dairy consumption may not be an accurate reflection of intakes over the course of the nine years of follow up and this reduces the certainty of the findings. The authors caution that readers should consider this study as only another piece of the evidence, and strong recommendations cannot be made for the consumption of higher fat (versus lower fat) dairy products. The study’s results only suggest that the consumption of dairy products may be encouraged for low and middle income countries and dairy products should not be discouraged for other consumers.
For additional discussion of the PURE study findings, see the PEN Trending Topic: Dairy Intake, Mortality and CVD – The Debate Continues.
- Louie JCY, Rangan AM. No need to change dairy food dietary guidelines yet. Lancet. 2018 Nov 24;392(10161):2242-4. doi: 10.1016/S0140-6736(18)31945-7. Epub 2018 Sep 11. Citation available from: https://www.ncbi.nlm.nih.gov/pubmed/30217461
Probiotics in the News
There is a lot of attention in social media lately about recent studies related to probiotics. The International Scientific Association for Probiotics and Prebiotics (ISAPP), which is an international group of probiotic scientists, provides critique of these studies. Click here for details.
Family Meals and Teen Diets
Teens Who Eat Meals with Family 'Have Healthier Diets' is a recent Behind the Headlines posting from the National Health Services (NHS) in the U.K. Research was conducted at the University of Guelph in Canada; Amherst College, Harvard Medical School and Brown University in the U.S.; and Loughborough University in the U.K. The study results showed, "not only do families with lower levels of family functioning participate in frequent family meals, but that family dinners are associated with improved dietary intake, regardless of level of family functioning". See Additional Content: Healthy Lifestyle - Eating Together Knowledge Pathway. Watch for updates to this PEN® content soon.
Just What Did the VITAL Results Teach Us About Vitamin D and Omega-3 Supplementation?
The Vitamin D and Omega-3 Trial (VITAL) was a very large randomized placebo-controlled study (with a two-by-two factorial design), which examined the effects of vitamin D or omega-3 supplementation on the primary outcomes: major cardiovascular (CV) events (myocardial infarction (MI), stroke, CV-related death) and invasive cancer (1,2). The study included 25,871 participants, 50 years or older for men and 55 years or older for women (20% of whom were black as prespecified in the study design). Participants were given 2000 IU/day vitamin D3 and 1 g/day of marine omega-3 fatty acids (either alone or in combination) or placebos. After five years, neither supplement resulted in significantly lower incidences of the primary outcomes, major CV events or invasive cancer, compared to the placebo. The outcomes were confirmed using medical records.
The bottom line is that neither vitamin D nor omega-3 fatty acid supplements lower the incidence of any invasive cancer or reduce major CV events. Further research is needed to determine if omega-3 fatty acids have any positive influence on reducing MIs among black people (a secondary finding).
In this study, researchers also looked at several other outcomes (MIs, stroke, cardiovascular deaths and deaths from any cause), which were considered secondary analyses (1,2). While most of these secondary analyses also suggested no benefits from either of these supplements, one of the observed secondary results might suggest that there could be a beneficial effect (lower risk of MI (HR, 0.72; 95%CI, 0.59 to 0.90) with supplementation of omega-3s (particularly in black participants (HR, 0.23; 95%CI, 0.11 to 0.47)). While this sub-analysis is interesting, it was not specified as a primary outcome at the start of trial, so it is possible that this statistical significance is due to chance alone. When many statistical tests are conducted, the probability of finding positive results increases with each additional test. Before secondary analyses should be considered to have any validity, they need to be tested as primary endpoints in adequately powered RCTs.
To assess whether the secondary result might suggest a benefit, it is important to examine its numerical value. The magnitude of the results for the overall reduction in MIs was (0.72 (95%CI, 0.59 to 0.90)) with supplementation of omega-3s. While this is statistically significant (the confidence interval did not include the null value of 1), the magnitude of the hazard ratio was greater than 0.5, a value that is considered to show a sufficient magnitude of change in health outcomes to represent an important difference (3). Using this metric, the secondary finding of reduced MIs among the black people supplemented with omega-3s (HR, 0.23; 95%CI, 0.11 to 0.47) suggests that it might be worth examining as a primary outcome in a subsequent study and the result for non-Hispanic white people suggests no effect at all of omega-3s on MI risk (HR, 0.93; 95%CI, 0.73 to 1.18).
For further discussion on the findings, see:
Vital Signs for Dietary Supplementation to Prevent Cancer and Heart Disease (Editorial)
VITAL: No CVD or Cancer Benefit from Vitamin D, Omega-3 (Free Membership Required to Access).
See PEN® Practice Questions:
Are vitamin D and/or calcium supplements recommended for prevention or treatment of cardiovascular disease (CVD)?
Should omega-3 fatty acids (fish or plant-based food or supplements be recommended for the primary or secondary prevention of cardiovascular disease (CVD) in adults?
- Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, et al.; VITAL Research Group. Vitamin D supplements and prevention of cancer and cardiovascular disease. N Engl J Med. 2018 Nov 10. doi: 10.1056/NEJMoa1809944. [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30415629
- Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, et al.; VITAL Research Group. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J Med. 2018 Nov 10. doi: 10.1056/NEJMoa1811403. [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30415637
- Guyatt GH, Oxman AD, Sultan S, Glasziou R, AKL EA, Alonso-Coello P, Atkins D, et al. GRADE guidelines: 9. Rating up the quality of evidence. J Clin Epidemiol. 2011 Dec;64(12):1311-6. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/?term=21802902
Food Sensitivity Tests
A recent article was published by CBC Marketplace about the misuse and misinterpretations of IgG tests for food intolerance. The article notes that medical experts, including the Canadian Society of Allergy and Clinical Immunology (CSACI), call IgG tests for food sensitivities “unvalidated,” and more than two dozen organizations warn about the misuse of such tests. Related information will be updated in the Food Allergies Knowledge Pathway soon.
Dairy Intake, Mortality and CVD - The Debate Continues
Proposed Global Consensus for Malnutrition Diagnosis Criteria
The Global Leadership Initiative on Malnutrition (GLIM), comprised of ASPEN, ESPEN, FELANPE and PENSA, released a Consensus Report from the Global Clinical Nutrition Community. The report proposes a global consensus construct for diagnosing malnutrition in adults in clinical settings. The recommended two-step approach starts first with screening to identify “at risk” status using validated screening tools, followed by assessment to diagnose and grade the severity of malnutrition.
For more malnutrition-related information see the PEN Malnutrition Knowledge Pathway. In addition, to learn more about how the:
Update on the Mediterranean Diet
How does the retraction and republication of the PREDIMED trial affect recommendations for a Mediterranean diet? The related PEN content was reviewed and updated accordingly:
The Mediterranean dietary pattern is recommended to lower the risk of cardiovascular disease (CVD).
Grade of Evidence B
A clinical trial from Spain (PREDIMED study) was retracted due to irregularities in the randomization procedures that included enrolling participants who were not randomized. In the PREDIMED trial, participants were randomized by advice to follow a Mediterranean (Med) diet supplemented with extra-virgin olive oil (50 g/4 Tbsp/day), a Med diet supplemented with nuts (30 g/day walnuts, hazelnuts and almonds) or a control, low fat diet. The study was reanalyzed by excluding participants (n=1588) who deviated from the randomization protocol; republished results did not change the overall results (1). After a follow up of five years, a 29-32% reduction in major CVD events (composite of myocardial infarction, stroke, or CVD mortality) was reported in both of the Mediterranean diet groups compared to the control. When the 1,588 participants were excluded from the analysis, the risk of major CVD events was: Med diet + olive oil group (hazard ratio (HR) 0.71; 95%CI, 0.52 to 0.97); Med diet + nuts (HR 0.68; 95% CI, 0.49 to 0.95). For individual components, only stroke risk was significantly reduced (Med diets combined HR, 0.58; 95%CI, 0.42 to 0.82). Effects on blood lipids were not reported.
For additional information, see the PEN Practice Question: In adults with elevated LDL-cholesterol (LDL-C), what are the effects of dietary patterns (i.e. Portfolio, Mediterranean, DASH) on LDL-C levels?
- Estruch R, Ros E, Salas-Salvadó J, Covas MI, Corella D, Arós F, et al.; PREDIMED Study Investigators. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med. 2018 Jun 21;378(25):e34. doi: 10.1056/NEJMoa1800389. Epub 2018 Jun 13. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29897866
Salt Intake and CVD: The Ongoing Debate
A Canadian and European Government- and NGO-funded study investigating the associations between community-level mean sodium and potassium intake, cardiovascular disease and mortality was recently published in The Lancet (1). The study reports on clinical outcomes based on an analysis of 94,378 participants from 18 countries. Participants were aged 35 to 70 years and did not have cardiovascular disease at baseline. As a surrogate for sodium intake, morning fasting urine was used to estimate 24-hour sodium and potassium excretion. The authors’ main interpretation was that sodium intake was associated with cardiovascular disease and stroke but only in communities where estimated mean sodium intake was greater than 5 g/day.
The validity of the results has been questioned by others (2,3) for two main reasons. First, this is an observational study based on community averages and not on individual data (ecologic study design). Second, 24-hour sodium excretion was estimated from urine collected after overnight fasting, which is not a reliable measurement of daily salt intake as is a repeated 24-hour urine sample. For more on the salt and hypertension debate, see Salt and Heart Disease: A Second Round of "Bad Science" and Expert Reaction to Study Looking at Salt Consumption and Health Risks.
See Additional PEN content: Does diet have a role in preventing hypertension?
- Mente A, O'Donnell M, Rangarajan S, Yeates K, Teo K, Yusuf S, et al. Urinary sodium excretion, blood pressure, cardiovascular disease, and mortality: a community-level prospective epidemiological cohort study. The Lancet. 2018 Aug;392(10146):496-506. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31376-X/fulltext
- Messerli FH, Hofstetter L, Bangalore S. Salt and heart disease: a second round of “bad science”? The Lancet. 2018 Aug;392:10146:456-8. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31724-0/fulltext?rss=yes
- Science Media Centre. Expert reaction to study looking at salt consumption and health risks. 2018 August 9. Available from: http://www.sciencemediacentre.org/expert-reaction-to-study-looking-at-salt-consumption-and-health-risks/
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