Search Health Studies

Search Results

Low-Carb Paleo Diet Linked with Unhealthy Changes to Gut Microbiome

Paleo diets tend to be high in meat and vegetables, while restricting all grains and dairy products. In this study, researchers analyzed the microbiome of 44 people who had been following a Paleo diet for at least 1 year, and 47 people who eat a healthy diet reflective of dietary guidelines. Those strictly following a Paleo Diet and those eating a standard healthy diet ate significantly more fiber than those only loosely following a Paleo diet. However, those who strictly followed the Paleo diet (eating the lowest levels of whole grains and total grains) were significantly more likely to have higher levels of TMAO (a compound generated by the gut microbiome that is associated with plaque buildup in the arteries). The authors also added that “the rationale to exclude whole grains is not supported by data presented here; being inversely associated with body weight and TMAO concentrations.”
European Journal of Nutrition. 2019 Jul 5. doi: 10.1007/s00394-019-02036-y. [Epub ahead of print] (Genoni A et al.)

Different Saturated Fats May Have Different Impacts on Health

Replacing saturated fats, like those in butter, cheese, and red meat, with unsaturated fats, like those in walnuts, olive oil, and avocados, can help reduce risk of heart disease. But are all saturated fats created equal? To better assess this relationship, scientists analyzed the diets of 2 large groups of European adults (from Denmark & the U.K.) totaling more than 75,000 participants, and then monitored their health outcomes more than a decade later. In one of the groups (the Denmark group), saturated fats from meat were linked with a higher risk of a heart attack, but other sources of saturated fat were not significantly linked with heart attack risk in either direction. Scientists also noted that lauric acid and myristic acid (saturated fats found in foods like coconut oil) were also linked with lower heart attack risk in the Denmark group, but not the U.K. group. More research is needed to better understand how different foods might relate to heart attack risk.
International Journal of Cardiology.  2019 Mar 15;279:18-26. doi: 10.1016/j.ijcard.2018.10.064. (Praagman J et al.)

Small Amounts of Red and Processed Meat Linked with Cardiovascular Death

Seventh-Day Adventism is a religion which promotes a vegetarian diet and overall healthy lifestyle as a spiritual practice. In this study, researchers followed a cohort of over 90,000 Seventh-Day Adventists for an average of about 12 years and analyzed their consumption of red and processed meats. They found that participants who ate the most red and processed meat tended to be less physically active, were more likely to smoke tobacco and drink alcohol, and had a lower intake of fruits, vegetables, legumes, and whole grains than the participants who ate no meat at all. Compared to vegetarians, participants who ate red and processed meat were more likely to die of any cause and of cardiovascular disease. Notably, the participants who ate the most red and processed meat in this study (about 1.5 ounces per day) still have a relatively low consumption when compared to the average American diet (sometimes closer to 5 ounces per day). This suggests that even a low consumption of red and processed meats may have negative health effects.
Nutrients.  2019 Mar 14;11(3). pii: E622. doi: 10.3390/nu11030622. (Alshahrani SM et al)

Red Meat Linked with Risk Factor for Heart Disease

TMAO is a potentially dangerous metabolite linked with heart attacks and stroke, so researchers wonder how diet can impact the amount of TMAO that our bodies produce. In this study, researchers assigned 113 adults to a high-saturated fat or low-saturated fat diet for 4 weeks, with a washout period before switching to the other diet. Interestingly, saturated fat did not impact TMAO. However, eating lots of red meat (but not white meat or nonmeat) was linked with significantly higher levels of TMAO through 3 different mechanisms (nutrient density of TMA precursors, increased production from carnitine, and reduced TMAO excretion).
European Heart Journal. 2018 Dec 10. doi: 10.1093/eurheartj/ehy799. (Wang Z et al.)

Protein from Nuts and Seeds Linked with Less Death from Heart Disease than Protein from Meat

Protein is important for our muscles, enzymes, and numerous essential body processes, but not all protein is created equal. To see how different protein sources relate to heart disease deaths, researchers carefully analyzed the diets of 81,337 men and women. Those getting more protein from nuts and seeds were significantly less likely to die from heart disease than those not getting as much protein from nuts and seeds. On the other hand, those getting more protein from animal sources had a higher risk of dying from heart disease. The relationship between heart disease death and these foods was so strong, even after controlling for other diet and lifestyle factors, that the researchers concluded that the link “could not be ascribed to other associated nutrients considered to be important for cardiovascular health.”
International Journal of Epidemiology. 2018 Apr 2. [Epub ahead of print] (Tharrey M et al.)

Whole Grains Linked with Healthier Arteries

Aortic stiffness, a thickening or hardening of the body’s main artery, naturally occurs due to aging but is accelerated by conditions like obesity and diabetes. Because aortic stiffness is a significant predictor of heart disease, heart failure and stroke, scientists wonder if lifestyle choices can help delay this progression. Researchers recruited 22 obese men to look at the stiffness of the aorta and ask questions about their dietary intake (e.g. fruits, vegetables, whole grains, meat, dairy, milk, etc.). Of all food choices, whole grains were the only factor significantly associated with less aortic stiffness.
Nutrition. 2018 Jan;45:32-36. (Campbell M et al.)

Moderate Cheese Intake Linked with Lower Risk of Heart Disease, Stroke

“Everything in moderation,” is a favorite adage of nutrition professionals, and for a good reason. Researchers in China analyzed the eating patterns and health outcomes of thousands of adults across 15 studies, to see how eating different amounts of cheese relates to heart disease. They found that eating more cheese was related to a 10-14% lower risk of heart disease and a 10% lower risk of stroke than eating less cheese, and that the greatest benefit was associated with eating about 1 ½ ounces (40g) of cheese per day. However, keep in mind that this is less cheese than most US and European adults are currently eating, at 42.5g and 49g respectively. Nonetheless, the researchers note that this adds to the growing body of evidence that not all saturated fats are created equal, and that cheese may not have the same health effects as red meat.
European Journal of Nutrition. 2017 Dec;56(8):2565-2575. (Chen GC et al.)

Heart-Healthy, Traditional Mediterranean Diets Can Work Anywhere if Properly Followed

The Mediterranean Diet gets lots of buzz, but do you know what it really means to eat like a Mediterranean? In a meta-analysis of 27 studies, researchers estimate that every 2-point increase in Mediterranean Diet Score (0-9 scale) is related to an 11% lower risk of heart disease. Additionally, the researchers also analyzed the consistency between Mediterranean Diet Scores in different studies, and clarified the importance of using a standard definition of a Mediterranean diet, which emphasizes “vegetables, fruits, nuts, legumes, and mainly unrefined, minimally processed cereals; an abundant fat intake from virgin olive oil… a moderate consumption of fish and shellfish, a low consumption of meat… the consumption of wine during meals… and fermented dairy products.” In order to successfully transfer Mediterranean diets outside of the Mediterranean, the researchers also note the importance of following the Mediterranean Diet eating patterns (such as drinking a moderate amount of wine with meals throughout the week, rather than binge drinking on weekends) and choosing traditional foods (such as olive oil and beans) rather than untraditional foods (such as margarine and tofu).
Nutrients. 2017 Nov 8;9(11). (Martinez-Gonalez et al.)

Butter isn’t “back,” according to the American Heart Association

In order to clear up confusion about how different dietary fats relate to heart health, the American Heart Association published a Presidential Advisory on Dietary Fats and Cardiovascular Disease. In this paper, the researchers reviewed randomized controlled trials (the gold standard of nutrition research) as well as prospective observational studies (following large groups of people over long periods of time and noting their health outcomes). After reviewing all of the evidence, they concluded that replacing saturated fat (the types of fats found in red meat, butter, and milk) with polyunsaturated fat (found in fish, nuts, and seeds) can lower the risk of heart disease by 30%, which is on par with what cholesterol lowering medications can achieve. Similarly, they found that eating more monounsaturated fat (found in avocados, olive oil, and canola oil), more polyunsaturated fat, and less saturated fat is linked with lower rates of heart disease. Saturated fat is also linked with higher rates of “bad cholesterol” (LDL), which is thought to build up in artery walls and pose a risk for heart disease. These findings are in line with healthy dietary patterns around the world, including the Mediterranean diet.
Circulation. 2017 Jun 15. [Epub ahead of print.] (Sacks FM et al.)

Healthier Diet May Reduce Greenhouse Gas Emissions & Cut Healthcare Costs

Healthy diets nourish both people and the planet, and the savings can be quite impressive. Scientists in California created models to analyze how greenhouse gas emissions and healthcare costs might change if we decrease red & processed meat and refined grains in our standard US diet, and shift to eat more beans and peas, whole grains, fruits, and vegetables. The researchers found that opting for the healthier diets can reduce risk of heart disease, colorectal cancer, and type 2 diabetes by 20-40%, saving the US $77-93 billion per year in healthcare. These shifts can also lower greenhouse gas emissions by 222-826 kg CO2, which is equivalent to 6-23% of the US Climate Action Plan’s target. Climatic Change. 2017 Mar 6. [Epub] (Hallstrom E et al.)

Replacing Animal Fats with Whole Grains, Polyunsaturated Fats, or Plant Proteins Linked with Less Heart Disease

Fat is essential to the diet, but certain fats are better than others. Scientists analyzed the eating patterns and health outcomes of more than 115,000 men and women in the Nurse’s Health Study and the Health Professionals Follow Up Study. The scientists found that those eating the most saturated fats (the types of fats found in red meat, butter, and milk) were more likely to get heart disease over the 24-28 year study period. In fact, replacing just 1% of calories from saturated fat with the same amount of calories from whole grains, polyunsaturated fats (found in fish, nuts, and seeds), or plant proteins (such as beans or nuts) is linked with a 6-8% lower risk of heart disease. The scientists conclude that “dietary recommendations for the prevention of coronary heart disease should continue to focus on replacing total saturated fat with more healthy sources of energy.”
British Medical Journal. 2016 Nov; 355:i5796. (G Zong et al.)

More Fish, Less Meat, Moderate Alcohol Intake Linked with Lower Heart Failure Risk

The Mediterranean diet is well known for its role in heart health, so researchers wanted to know if the foundations of a Mediterranean diet specifically reduced the risk of heart failure. German researchers analyzed the diets of 24,008 middle aged European adults, and followed their health outcomes for 8 years. While a strong adherence to a Mediterranean diet was not significantly related to lower heart failure risk after adjusting for other risk factors, many components of the Mediterranean diet were linked with a lower risk of heart failure, including high fish intake, moderate alcohol intake, and low meat intake. The researchers conclude that “Minor dietary changes could be valuable primary prevention measures, particularly the increase of fish consumption while reducing the intake of meat.”
European Journal of Clinical Nutrition. 2016 Sep;70(9):1015-21. (Wirth J et al.)

Pages