Science Update: New Studies on the Benefits of Plant-Based Diets

In the world of science, research is non-stop. Recent months have been no exception. Throughout 2018 and continuing into 2019, results of a multitude of studies have been published, including many placing plant-based diets under the spotlight. The favourable consequences of the plant-based way of eating are numerous, powerful and far-reaching. The following is an overview of some of these recent investigations.

Plant-Based Diets Improve Calorie Burning After Meals (1)

A study from April 2019 found that eating larger meals that are plant-based (high in whole carbohydrates and protein and low in fat) can increase the burning of calories after eating. In other words, eating plant-based raises the body’s metabolic rate. Specific lifestyle factors that accomplish this result include higher intake of fruits, vegetables and fiber as well as increased physical activity. With two-thirds of North American adults now overweight or obese, new methods for weight management such as a lifestyle change to a whole food plant-based diet may help those struggling with weight issues.

 

Plant-Based Diets Promote a Healthy Microbiome (2)

It is well-recognized that the composition of the gut microbiota in vegans and vegetarians is quite different from that of omnivores. Nutrients exclusive to plants such as non-digestible fiber and antioxidants like polyphenols encourage a diverse and stable population of beneficial bacteria to thrive in the gut while discouraging harmful species. These microorganisms have a myriad of positive health effects. For instance, they produce short-chain fatty acids that strengthen immunity, promote the integrity of the blood-brain barrier and improve intestinal function. They help to fight off disease-causing organisms. They reduce inflammation and lower the risk of cardiovascular disease. A literature review from April 2019 concluded that a plant-based diet is the most effective way to optimal gut health.

Plant-Based Diets Reduce Risk for Preterm Birth and Other Complications of Pregnancy (3)
A systematic review was published in the American Journal of Clinical Nutrition in March, 2019. Results revealed a number of benefits for both mothers and babies if the mothers were eating a plant-based diet.

Plant-based diets higher in fruits, vegetables, whole grains, nuts and seeds and lower in red and processed meat and fried foods were associated with lower risk for preterm birth. Babies born preterm have increased risks for complications involving hearing, vision, breathing and delayed motor and cognitive skills.

Plant-based diets higher in vegetables, fruits, whole grains, nuts, legumes, fish, and vegetable oils and lower in meat and refined grains were associated with reduced risk of hypertension (high blood pressure) during pregnancy.

Plant-based diets higher in vegetables, fruits, whole grains, nuts, legumes, and fish and lower in red and processed meats were associated with reduced risk of gestational diabetes mellitus (diabetes occurring during pregnancy).

 

Plant-Based Diets Reduce Risk of Gallstones (4)

Plant-based diets contain high levels of fiber, a nutrient which lowers cholesterol. Fiber is thought to be the most likely mechanism for the reduced incidence of gallstones in vegetarians. A prospective study from February 2019 followed almost 5,000 participants and found that women eating a non-vegetarian diet had twice the risk of gallstones compared with women consuming a vegetarian diet. Additionally, women with high cholesterol had almost four times the risk for gallstones compared with vegetarian women with normal cholesterol levels. Moreover researchers observed that fiber can protect against other risk factors including insulin resistance and obesity.

 

Plant-Based Diets are Healthiest for Kidney Disease Patients

Research from August 2018 discovered that not only do plant-based diets satisfy nutritional requirements for patients with kidney disease, they also offer other health benefits. Health professionals once worried that plant-based diets would not provide enough protein to their kidney disease patients and recommended the consumption of animal-sourced protein. It is now becoming apparent that animal protein could actually be dangerous to kidney patients, potentially worsening metabolic acidosis and increasing blood pressure and blood phosphate levels. And there need be no concerns that plants cannot supply sufficient protein. Plant-based diets are more than adequate in protein content. (5)

Another recent study, published in May 2019, looked at the relationships between plant-based diets, decline in kidney function and development of Chronic Kidney Disease (CKD) in almost 15,000 participants who were followed over the course of thirty years. Results revealed that participants who most closely followed a healthy plant-based diet were 14% less likely to develop CKD than those who least adhered to the diet. In addition, plant-based diets were associated with a slower decline in kidney function. This study distinguished between various types of plant-based diets. Healthy plant-based diets (high in whole grains, fruits, vegetables, nuts, and legumes) were associated with the largest reduction in CKD. In contrast, those eating the least healthy plant-based diets (high amounts of refined grains, sweets, sugar-sweetened beverages, potato or corn chips, French fries and fruit juices) were associated with an 11% higher risk of CKD. Study authors credit dietary fiber as the likely factor causing the protection from CKD arising from dietary factors (6). This study adds to the results of a 2017 investigation that found a significant reduction in risk of chronic kidney disease by replacing one daily serving of red and processed meat with plant sources of protein. (7)

 

Plant-Based Diets Are Good For the Heart

A review of clinical trials and observational studies from May/June 2018 found consistent evidence that completely plant-based vegan diets are associated with healthier cardiovascular systems. This dietary pattern has a multitude of benefits (8);
Reduction of cardiovascular disease mortality
Reduced risk of myocardial infarction
Reduced risk and reversal of coronary heart disease
Prevention and reversal of atherosclerosis
Prevention and treatment of heart failure
Prevention and treatment of cerebrovascular disease
Decreased blood pressure
Decreased blood lipid levels
Decreased body weight
Reduced tendency of blood to clot
Reduced risk of metabolic syndrome
Reduced risk of type-2 diabetes
Weight management

A systematic review and meta-analysis also from May/June 2018 revealed that a specific plant-based diet known as the “Portfolio Diet” can prevent heart disease in people with high cholesterol. The Portfolio diet is a plant-based diet that contains prescribed daily amounts of tree nuts and/or peanuts; viscous soluble fiber from oats, barley, psyllium, eggplant, okra, apples, oranges and berries; and plant sterols from peas, peanuts, kidney beans, broad beans, wheat germ or plant-sterol containing margarine. The Portfolio diet can reduce LDL-cholesterol by about 17% and, in addition, also decreases other blood lipids, blood pressure and C-reactive protein. In addition, the 10-year coronary heart disease risk is decreased by about 13% in those consuming a Portfolio Diet (9).
An April 2019 study from the Journal of the American College of Cardiology compared five eating patterns, including plant-based and Southern dietary patterns, with heart disease incidence in more than 16,000 adult participants. Eating a plant-based diet resulted in a 41% lower risk for heart failure when compared to those with the lowest adherence to plant-based eating. Southern eating patterns, rich in fried foods, processed meats, eggs, added fats and sweetened drinks, produced a 72% increase in risk of heart failure. From the study results, researchers recommended a healthy diet emphasizing vegetables; plant proteins such as lentils, nuts, chickpeas, tofu and beans; and limiting consumption of meat. The anti-inflammatory effects of antioxidants, abundant in a diet made up of mainly plants, were credited with the beneficial effects observed in eaters of a plant-based diet (10)

 

Plant-Based Diets are the Optimal Way to Better Overall Health

A meta-analysis from December 2018 shows that those eating a plant-based diet have fewer health risk factors compared to those eating an omnivorous diet. People eating plant-based consume fewer calories and less saturated fat and have lower body mass, LDL-cholesterol, triglycerides, blood pressure and fasting blood glucose (11).
And finally, eating more plant-based foods is associated with lower likelihood of gaining weight over a lifetime than eating animal-based foods, refined grains, fried foods and sweet. This conclusion was reached by Harvard researchers who analyzed the results of three large cohort studies, the Nurses’ Health Study, the Nurses’ Health Study 2 and the Health Professionals Follow-up Study, that included over 126,000 participants and more than twenty years of follow-up (12).
Turning to a plant-based diet in 2019 is much easier than it has ever been in the past. Information on healthy eating is freely available on the internet where delicious, quick and easy recipes are plentiful and free. Many restaurants are offering a variety of plant-based menu options. Scientific evidence of the many startling benefits of eating simply plants is abundant and indisputable. With one lifestyle change able to reduce so many health risk factors, isn’t it time you gave it a try?

 

SOURCES

1 Calcagno, M., Kahleova, H., Alwarith, J., et al. The thermic effect of food: a review. J Am Coll Nutr. Published online April 25, 2019. DOI: 10.1080/07315724.2018.1552544

2 Tomova, A., Bukovsky, I., Rembert, E., et al. The effects of vegetarian and vegan diets on gut microbiota. Front Nutr. Volume 6, Article 47. Published online April 17, 2019. DOI: 10.3389/fnut.2019.00047.

3 Raghavan, R., Dreibelbis, C., Kingshipp, B.L., et al. Dietary patterns before and during pregnancy and birth outcomes: a systematic review. Am J Clin Nutr. March 2019;109:729S-756S.

4 Chang, C.M., Chiu, T.H.T., Chang, C.C., Lin, M.N., Lin, C.L. Plant-based diet, cholesterol, and risk of gallstone disease: a prospective study. Nutrients. Feb 4, 2019; 11(2): 335-349.

5 Joshi, S., Shah, S., Kalantar-Zadeh, K. Adequacy of plant-based proteins in chronic kidney disease. J Ren Nutr. Published online August 16, 2018.

6 Kim, H., Caulfield, L.E., Garcia-Larsen, V., Steffen, L.M., Grams, M.E., Coresh, J., Rebholz, C.M.. Plant-Based Diets and Incident CKD and Kidney Function. Clin J Am Soc Nephrol. 2019 May 7;14(5):682-691.

7 Haring, B., Selvin, E., Liang, M., Coresh, J., Grams, M.E., Petruski-Ivleva, N., Steffen, L.M., Rebholz, C.M. Dietary Protein Sources and Risk for Incident Chronic Kidney Disease: Results From the Atherosclerosis Risk in Communities (ARIC) Study. J Ren Nutr. 2017 Jul;27(4):233-242.

8 Kahleova, H., Levin, S., Barnard, N.D. Vegetarian dietary patterns and cardiovascular disease. Prog Cardiovasc Dis. May-June 2018; 61(1): 54-61.

9 Chiavaroli, L., Nishi, S.K., Khan, T.A., et al. Portfolio Dietary Pattern and Cardiovascular Disease: A Systematic Review and Meta-Analysis of Controlled Trials. Prog Cardiovasc Dis. May-June 2018; 61(1): 43-53.

10 Lara KM, Levitan EB, Gutierrez OM, et al. Dietary patterns and incident heart failure in U.S. adults without known coronary disease. J Am Coll Cardiol. April 2019;73:2036-2045, 2046-2048.

11 Benatar, J.R., Stewart, R.A.H. Cardiometabolic risk factors in vegans; a meta-analysis of observation studies. PLOS ONE. December 2018; 13. e0209086. 10.1371/journal.pone.0209086.

12 Satija, A., Malik, V., Rimm, E.B., Sacks, F., Willett, W., Hu, F.B. Changes in intake of plant-based diets and weight change: results from 3 prospective cohort studies. Am J Clin Nutr. Published ahead of print May 25, 2019.