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.
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/
A2 Milk Revisited
A recent article, A2 Milk: Breakthrough of Science or Marketing? published in Medscape* highlights the debate concerning the health benefits of A2 milk. A2 milk will soon be available for purchase in the United States. This recent article supports the Bottom Line in the PEN® analysis posted in January 2018. See the Trending Topic Does A2 Milk Have Health Benefits?
*You may be required to register (free) to view the Medscape article.
Lectins – Are They Damaging to Our Health?
Malnutrition in Infants Fed Plant-based Beverages
Cases (n=34) of protein-energy malnutrition have been described in France among infants who were fed plant-based beverages/drinks (age at diagnosis 8.8 + 3.8 months) (1). These cases were discovered when pediatricians were asked to see these children because of fatigue or a growth deficit. One of these infants died, one-third had malnutrition, 29% (10/34) had a seizure, one suffered from respiratory distress and one had a bone fracture. Among the children who had blood work done, 60% (12/20) had anemia, 55% (11/20) had hypoalbuminemia, and 40% (8/20) had hyponatremia. The children were all fed plant-based drinks, mostly almond, chestnut and rice drinks. Previous reports involved smaller numbers of children (2).
The infants’ health improved after resuming a normal infant diet (which was not described), although one-third of the parents were not happy about the change in diet (1). The parents stated that their main influencers to give the plant-based drinks to their infants were the media (44%) and “alternative medical professionals” (38%). The researchers attributed the malnutrition to the low protein and energy contents of these drinks.
Although it is not possible to state with certainty that the malnutrition was caused by the plant-based drinks, the fact that 30 children (who were assessed) overcame their illnesses when placed on a normal infant diet suggests that this was the case. These cases may represent the health halo, a belief that these drinks are healthier than other choices.
For information on the recommendations for the use of plant-based beverages in infants, see PEN® Practice Question: What are the recommendations for the use of plant-based beverages (e.g. soy, rice, almond, coconut and oat milk/beverage) during the complementary feeding period in infants?
- Lemale J, Salaun JF, Assathiany R, Garcette K, Peretti N, Tounian P. Replacing breastmilk or infant formula with a nondairy drink in infants exposes them to severe nutritional complications. Acta Paediatr. 2018 Jun 20. doi: 10.1111/apa.14437. [Epub ahead of print]. Citation available from: https://www.ncbi.nlm.nih.gov/pubmed/?term=29923219.
- Dietitians of Canada. Trending Topics: Plant-based Beverages – Are They Really Healthier for Young Children? In: Practice Based Evidence in PEN® [PEN]. 2017 Aug 29. Available from: http://www.pennutrition.com/resourcestools.aspx?trcatid=496&trid=26285&sr=plant-based#. Access only by subscription.
The Science and Politics of Nutrition Series - The History of Nutrition Science
The BMJ has launched a series of open access, peer-reviewed articles under the title, Food for Thought - The Science and Politics of Nutrition. The series covered 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. The first article of the series describes the history of nutrition science and how this history has formed our current understanding of
diet and health as well as the current controversies that we deal with every day.
Note: This is the first article in the launch of a series of articles. We will post other appropriate articles in the coming weeks and months. These articles cover topics ranging from the role of carbohydrates in chronic disease to the quality of dietary guidelines. The complete collection of articles can be downloaded from Food for Thought.
Skinny Teas and Weight Loss
With weight loss teas becoming fairly common due to claims about dramatic weight loss in online advertisements, Clare Collins, a professor in Nutrition and Dietetics at the University of Newcastle in Australia, conducted a literature search to investigate if skinny teas do in fact boost weight loss. She did not find any related studies specific to "slimming teas". In her analysis of 11 research studies related to green tea, black tea and tea mixtures she concluded that "skinny teas might not have any properties to help you lose weight, but they might remind you you’re on a diet". See more information about her findings at: The Conversation.
The American Gut Project is the first crowd-funded, citizen scientist cohort that examined the microbial sequence data of 15,096 samples from >10,000 human participants from the United States, United Kingdom and Australia. The researchers set out to examine the diversity of the industrialized human microbiome, and to look for associations between health, lifestyle and dietary factors. The researchers found that participants who reported consuming ≥30 different types of plant species each week had greater microbial diversity than those who reported consuming only ≤10 types of plant species weekly. Self-categorization of diet as “vegan” or “omnivore” had less of an impact on microbial diversity than quantification of the numbers of plant species consumed. The hypothesized implications of having greater microbial diversity is that more microbial species may be available to act as the fermenters of short-chain fatty acids. Therefore, a diet containing a variety of dietary fibres and resistant starches is likely to contribute to a more diverse microbial community. In addition, the participants who reported eating >30 types of plants per week had a significantly lower abundance of bacteria that carry antibiotic-resistant genes. This observational study cannot conclude causality but provides some food for thought related to dietary practices and future research focused on microbial diversity and health. Posted: 2018-05-18
See Additional Content: Gastrointestinal System – Microbiota Background
Misleading News Headline Regarding Egg Consumption
This trial recently appeared in the news, Nutrition Journal Suggests New Guidelines for Egg Consumption, with the researchers concluding that, "a healthy diet based on population guidelines and including more eggs than currently recommended by some countries may be safely consumed". The PEN® System recently updated this Practice Question: Are interventions to decrease cholesterol intake (e.g. restricting eggs) recommended for the secondary prevention of cardiovascular disease (CVD)? The evidence used to answer the question includes a systematic review that reports earlier results of the trial mentioned above along with five other randomized controlled trials, which found that regular egg consumption had no adverse effects on blood lipid levels. All of these trials were assessed at high risk of bias (primarily for lack of allocation concealment and failure to blind participants/personnel) and they all received funding from egg boards/councils. In contrast to these findings, a high egg intake (i.e. >1 egg/day versus <1 egg/week) has been associated with an increased risk of coronary heart disease in individuals with diabetes. A high dietary cholesterol intake (>200 mg/day) can also increase serum cholesterol levels in some people and there is a lack of harm from restricting dietary cholesterol.
Therefore, the PEN recommendation, based on very low quality evidence, suggests restricting dietary cholesterol to ≤200 mg/day (e.g. by reducing egg consumption to <1 egg/week) to reduce CVD events for adults with diabetes, dyslipidemia or established CVD. For practice guidance, see the updated PEN client handout: Eating Guidelines for People with High Blood Cholesterol.
This recommendation does not apply to adults at low CVD risk. For information on eggs for the general population, see PEN Practice Question: Are interventions to decrease dietary cholesterol intake (e.g. restricting eggs) recommended for the primary prevention of cardiovascular disease (CVD)?
Trending Topic: Recent Research on Vitamin D
Trending Topic - Do New Parents or Parents-to-be Need to be Concerned with Dietary Arsenic Exposure?
Are Your Clients Asking About "Leaky Gut Syndrome"?
There is little human evidence to support the theory that a "leaky gut" is the direct cause of any significant, widespread health problem. Read more at: "Leaky Gut Syndrome", Debunking the Myth of "Leaky Gut Syndrome" and Intestinal Permeability Defects: Is it Time to Treat?
Until more evidence is available on intestinal permeability, dietitians can educate their clients on nutritiously balanced diets based on nutrition assessment and evidence. Clients should be encouraged to be wary of any alternative program/diet that promises “magical results”.
Reposted from January 2017.
Updated Diabetes Clinical Practice Guidelines
The following two clinical practice guidelines (CPGs) have been updated:
- Diabetes Canada: 2018 Clinical Practice Guidelines and Quick Reference Guide
- Diabetes UK: Evidence-based Nutrition Guidelines for the Prevention and Management of Diabetes (March 2018)
The PEN Team is in the process of adding these guidelines to the 13 diabetes knowledge pathways in PEN.
Trending Topics: Plant-based Beverages – Are They Really Healthier for Young Children? (Reposted from Aug 29, 2017)