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.
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
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
Trending Topics - Plant-based Beverages – Are They Really Healthier for Young Children? (Reposted from Aug 29, 2017)