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.
Carbohydrate, Fat and Mortality
The study, Associations of Fat and Carbohydrate Intake with Cardiovascular Disease and Mortality in 18 Countries from Five Continents (PURE): A Prospective Cohort Study, stemming from the PURE macronutrient studies, has been getting a lot of press across the globe (e.g. Canada, U.K.). This is a very large international cohort comprising high, middle and low income countries. It is an observational analysis with dietary intake collected by self-reported food frequency questionnaires (FFG) at baseline only. After looking at a range of carbohydrate (46-77% of energy) and saturated fat (2.8-13.2% of energy) intake (not a typical range seen in North America or Europe) the authors found that high carbohydrate intake was associated with a higher risk of total mortality, and non-cardiovascular disease mortality (e.g. cancer, respiratory diseases).
For analysis on the study, see: NHS Choices - Behind the Headlines
For further analysis on the study, see The Conversation: New Study Finding Fat Isn't as Bad as Carbs Misses the Point
For more information, see PEN Additional Content:
Practice Question: Is a Reduced Saturated Fat Diet Recommended for Primary or Secondary Cardiovascular Disease Prevention?
Evidence Clip: Butter, Margarine, Saturated and Trans Fats - Making Sense of Research Reported in the News
Fresh, Fresh-stored and Frozen Vegetables and Fruit
A two-year study (2011-2013) compared L-ascorbic acid, folate and trans-B-carotene (pro-vitamin A) in three different process states of products: fresh, fresh-stored (held for five days in the refrigerator) and frozen produce (blueberries, broccoli, cauliflower, corn, green beans, green peas, spinach and strawberries). Produce was purchased from six supermarkets within a 40-km radius of Athens, GA in the U.S. Within the majority of comparisons, the authors found no significant differences in the three nutrients between fresh, fresh-stored and frozen produce. Where significant differences were noted, the nutrient content of fresh and frozen varieties tended to be greater than fresh-stored produce. Exceptions included fresh versus frozen blueberries, green beans and spinach, with fresh having a greater content of trans-B-carotene, and frozen broccoli and green beans, which were lower in folate than their fresh counterparts. The authors suggest consumers consume their fresh produce as soon as possible after purchase. Authors declared this research was supported by a grant from the Frozen Food Foundation.
Trending Topics: Plant-based Beverages – Are They Really Healthier for Young Children?
Article Analysis: Plant-based Diets and Chronic Disease
Food Insecurity and Chronic Disease
A recent report from the U.S. Department of Agriculture describes the negative impact poor nutrition can have on an adult's health. The report, Food Insecurity, Chronic Disease, and Health Among Working-Age Adults used 2011-2015 data obtained from the National Health Interview Survey (NHIS), a source for national statistics on the health of the U.S. population. The report examined food insecurity as a predictor of health among working adults (41,854 total adults from households; ages 19-64 years) living at or below 200% of the U.S. federal poverty line. The differences in health outcomes (related to 10 chronic diseases) across the range of household food insecurity: high, marginal, low and very low were examined. Food insecurity was found to be significantly associated with all 10 of the chronic diseases studied. Individuals with low and very low food insecurity had higher rates of high blood pressure, heart disease, cancer, asthma, diabetes, arthritis, kidney disease, hepatitis, stroke and chronic obstructive pulmonary disease. These changes in disease prevalence rates by food insecurity status were statistically significant for all of the conditions studied. For all of these diseases, an individual's food insecurity predicted chronic illness rates in a dose-response way. As food security changed from food secure through to highly food insecure, the disease prevalence was higher as food insecurity worsened, with the highest rates for each of these diseases most prevalent among individuals with very low food security.
For country-specific positions see:
Nonnutritive Sweeteners, Body Weight and Cardiometabolic Health - Inconclusive Results
A recent systematic review and
meta-analysis of the health impact of nonnutritive sweeteners (e.g. aspartame, sucralose, stevioside) was recently published in the Canadian Medical Association Journal. The authors concluded that nonnutritive sweeteners may not help weight loss. While the observational studies suggested that regular intake may be associated with an increase in BMI, randomized trial evidence found no effect of these sweeteners on BMI. The observational studies found that nonnutritive sweetener use was associated with increased cardiometabolic risk (i.e. type 2 diabetes, stroke, high blood pressure and metabolic syndrome); however, these outcomes were not assessed in the randomized trials. Based on the differences regarding weight changes between the studies of the two design types, it is possible that people who routinely use nonnutritive sweeteners may be at higher risk of weight gain or have lifestyles that increase their risks of adverse metabolic outcomes and the sweeteners may not be the cause of these problems. An NHS
Behind the Headlines article has pointed out important limitations of the existing
research and concluded that more research is needed to confirm the positive and
negative health impacts of nonnutritive sweeteners. For more information on
sweeteners, see PEN
Knowledge Pathway - Sweeteners.
Obesity Prevention and Management
The Canadian Task Force on Preventive Health Care (CTFPHC) recently released a free e-learning course called, Obesity Prevention and Management, to help clinicians understand the guideline recommendations, the evidence underlying the recommendations, strategies for implementing the recommendations, and the differences between the CTFPHC guidelines and guidelines developed by other groups. The CTFPHC guidelines, Obesity in Adults and Obesity in Children, published in 2015, were developed by primary care and prevention experts across Canada and are based on systematic analysis of scientific evidence.
Trans Fats on Their Way Out Again!
Health Canada has published a Notice of Proposal (Information Document) signalling its intent to implement the prohibition on the use of partially hydrogenated oils (PHOs) in all foods by adding PHOs to Part 1 of the List of Contaminants and Other Adulterating Substances in Foods. This prohibition is proposed to take effect in the summer of 2018, which would allow industry stakeholders time to phase-out the use of PHOs. Interested stakeholders are invited to share and provide comments on the proposal by June 21, 2017 and can view further information on the proposals as well as a summary of comments received during the previous public consultation at Notice of Proposal (Prohibiting the Use of PHOs in Foods).
Article Analysis: Dementia, Stroke and Sugary and Artificially Sweetened Drinks
Benefits of Reducing Saturated Fat Intake Criticized
A recent editorial by Malhotra, et al. made headlines claiming that reducing saturated fat intake has no effect on coronary heart disease. The authors do not cite the best or most recent evidence to support this claim. Importantly, they fail to acknowledge the results of a recent Cochrane review, which found moderate quality evidence that reducing saturated fat intake decreased cardiovascular (CV) events (including CV deaths, CV morbidity or unexplained CV interventions) in populations at low, moderate and high risk (1). When talking about reducing saturated fat intake, it is important to consider the replacement calories. Recent evidence identifies that the greater reductions in CV events occurred when saturated fat was replaced with polyunsaturated fat, but not with carbohydrate (1). The editorial does emphasize the benefits of a whole dietary approach, such as the Mediterranean diet, instead of focusing on specific nutrients. There is merit to this approach. The Mediterranean diet pattern is low in saturated fat and includes rich sources of unsaturated fat such as oils, nuts, seeds and oily fish, in addition to plenty of legumes, vegetables, fruit and whole grains. See additional commentary from David Katz published in Linkedin: Sat-Fat Bait & Switch.
Seems we were not alone in our concerns about the opinion piece that garnered media attention last week. Further expert reaction from the U.K. to the editorial on saturated fat and heart disease is available from Science Media Centre.
See Additional Content: Is a reduced saturated fat diet recommended for primary or secondary cardiovascular disease (CVD) prevention?
Hooper L, Martin N, Adbelhamid A, Dave Smith G. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 2015 Jun 10;(6):CD011737. doi.10.1002/14651858.CD011737. Abstract available from: http://www.ncbi.nlm.nih.gov/pubmed/26068959
Article Analysis: Intensive Lifestyle Counselling and Improving Glycemic Control
A Resource for Health Care Professionals on the Practice of Sharing Human Milk
Perinatal Services BC has published a resource that provides health care professionals with information and the tools to facilitate a discussion and make decisions regarding the informal sharing of unpasteurized donor human milk (UDHM). Informal sharing involves the sharing of UDHM between friends, family members or online social networks, or the purchase of UDHM outside of the regulated milk banks. The practice of sharing UDHM is increasing and the resource, Informal (Peer-to-Peer) Milk Sharing:The Use of Unpasteurized Donor Human Milk, provides practice information on the risks and benefits of supplemental options (mother’s own milk, pasteurized donor human milk from regulated milk banks, commercial infant formula), how to minimize the risks of informal milk sharing, ethical and legal considerations, and other decision support tools.
The World Health Organization recommends exclusive breastfeeding for the first six months of life to achieve optimal development, growth and health (1). There are many benefits of breastfeeding; however, the BC resource may overstate the benefits as the cited health outcomes research are based on observational studies that are limited by the inadequate control of confounding factors. For information on the health outcomes for breastfed infants see the Infant Nutrition - Breastfeeding Knowledge Pathway. Also not mentioned in the BC resource - Appendix 5: Family Information Handout, is the high cost of pasteurized donor human milk. For additional information on this topic see PEN Evidence Clip: The Dangers of Sharing Unpasteurized Milk.
1. World Health Organization and UNICEF. Global strategy for infant and young child. 2003. Available from: http://www.who.int/nutrition/publications/infantfeeding/9241562218/en/
Can an intentional nudge influence decision-making towards choosing a healthier dietary option? A recent study, The Efficacy of Nudge Theory Strategies in Influencing Adult Dietary Behaviour: A Systematic Review and Meta-analysis in BioMed Central (BMC) Public Health, says it can. Nudge theory, or 'nudge' proposed by Thaler and Sunstein (2008) in their book, Nudge: Improving Decisions About Health, Wealth and Happiness, is based on providing indirect suggestions that guide voluntary shifts in behaviour towards choosing the healthier option. The BMC review assessed nudge effectiveness as a strategy in influencing adults (a generic population of men and women; 18-65 years) to change their dietary choices from unhealthy (foods high in fat, salt or sugar) for healthier ones (more nutrient dense, i.e. the consumption or purchase of more vegetables, fruit and whole grains; and lower in calories, salt, sugar, cholesterol or fat). The researchers systematically searched and quantitatively assessed (meta-analysis) 42 studies (31 RCT; two cohort; and nine cross-sectional) aimed at influencing behaviour related to food consumption. The interventions involved knowledge-based changes (e.g. menu labelling), availability of food (e.g. convenience or adjusting portion size), changes to the social environment or emotional priming. Most of the studies took place in a lab setting (48%) or in a cafeteria (17%) and were conducted predominantly in the U.S. The studies were analyzed based on their percent change in frequency of a choice or in the consumption/purchases made (outcome categories were calories, grams or purchases; either quantity purchased or monetary amount). The researchers found that, on average, nudge interventions lead to a 15.3% (95%CI, 7.6 to 23%) increase in healthier consumption/nutritional choices, as measured by the frequency of healthy choices or by overall intake of healthier food. While the generalizability of the findings is limited by the wide variety of interventions included and nudge-related research in more geographically and varied populations is needed, this paper provides some of the basics and justification for implementing nudging strategies into practice.