Diets can be difficult to stick to over extended periods of time, and the health benefits aren’t always long lasting. In this study, researchers analyzed 121 studies encompassing 21,942 people looking at the impacts of 14 popular diets (Mediterranean diet, low carb diet, low fat diet, etc.) after 6 months and 12 months. After 6 months, most of the diets resulted in a modest weight loss as well as improvements in blood pressure and LDL (“bad”) cholesterol. However, after 12 months, weight loss had diminished, and only those on a Mediterranean diet continued to see lower blood pressure.
BMJ. 2020 Apr 1;369:m696. doi: 10.1136/bmj.m696. (Ge L et al.)

A traditional Mediterranean diet includes frequent seafood and frequent but small portions of dairy foods, leaving some to wonder how a Mediterranean diet relates to markers of bone health. In this study, researchers analyzed the diets and vitamin D levels (using 25(OH)D blood levels) of 284 overweight and obese adults in Italy. Vitamin D levels in the blood are important to study, as they can indicate whether someone’s bones are strong or at risk of osteoporosis. Those most closely following a Mediterranean diet were significantly more likely to have higher vitamin D levels, as well as to have healthier BMI, waist size, insulin levels, and triglycerides (a type of fat in the blood). Seafood, which is abundant in the Mediterranean diet, is an important source of vitamin D, and the authors suggest that vitamin D may partially explain the Mediterranean diet’s protective effect on osteoporosis.
Int J Food Sci Nutr. 2020 Mar 29;1-7. doi: 10.1080/09637486.2020.1744533. Online ahead of print. (Zupo R et al.)

Lung function gradually declines with aging, but certain lifestyle changes may be able preserve lung function for a longer period of time. In a study of more than 2,000 adults ages 50+, those most closely following a Mediterranean diet had better lung function (as measured by peak expiratory flow rate) than those not following a Mediterranean diet, even after adjusting for factors like age, smoking history, and physical activity. When looking at specific foods, grains, dairy foods, and fish were all linked with better lung function.
Journal of the American College of Nutrition. 2020 Mar 23:1-6. doi: 10.1080/07315724.2020.1740114. [Epub ahead of print] (Papassotiriou I et al.)

Vegetarians tend to be healthier than their meat-eating counterparts, though some are at risk of falling short on Vitamin B12 (found in animal foods or in supplements). In this study, researchers followed more than 13,000 adults in Taiwan for up to 9 years to see how vegetarianism related to stroke risk. Vegetarians had a significantly lower risk of stroke compared with people who ate meat and fish. Interestingly, when comparing vegetarians who get adequate vitamin B12 with vegetarians who fall below vitamin B12 recommendations, it was only the subgroup of vegetarians with inadequate vitamin B12 (less than 2.4 μg) that had a lower risk of stroke.
Neurology. 2020 Mar 17;94(11):e1112-e1121. doi: 10.1212/WNL.0000000000009093. Epub 2020 Feb 26. (Chiu THT et al.)

Many times when people think they don’t like a particular food, what’s really happening is that they aren’t yet familiar enough with it. To see how this theory might apply to whole grains, researchers took 45 people who don’t eat whole grains and randomly assigned half of them to a diet with whole grains (where they were gifted whole grain products to incorporate into meals and snacks) for 6 weeks, while the other half continued eating their normal diet. Those in the whole grain group rated whole grains’ flavor and texture more favorably than they did before, and also expressed more willingness to include whole grains as a regular part of their diet.
Curr Dev Nutr. 2020 Mar 9;4(3):nzaa023. doi: 10.1093/cdn/nzaa023. eCollection 2020 Mar. (De Leon A et al.)

A balanced diet is important to support our bodies and our brains as we age. In a study of 139,096 Australian adults followed for 6 years, those eating the most fruits, vegetables, and protein foods had a lower risk of developing memory loss, while those eating the most fruits and vegetables also had the lowest risk of comorbid heart disease. When looking specifically at adults over 80 years old, those eating the fewest grains had the highest risk of memory loss and comorbid heart disease.
Int J Public Health. 2020 Feb 12. doi: 10.1007/s00038-020-01337-y. Online ahead of print. Xu X et al.)

A well-balanced diet is one of the best ways to set our bodies up for good health down the road, and transplant patients are no exception. In this study of 632 adult kidney transplant recipients, those most closely following a Mediterranean diet had a 32% lower risk of graft failure and kidney function decline, and a 26% lower risk of graft loss (graft being the term for the transplanted kidney).
Clinical Journal of the American Society for Nephrology. 2020 Feb 7;15(2):238-246. doi: 10.2215/CJN.06710619. (Gomes-Neto AW et al.)

Don’t let a poor diet keep you up at night. In this study, researchers analyzed the diets and insomnia rates of more than 50,000 post-menopausal women. Eating more whole grains, fiber, fruit, and vegetables was linked with lower odds of insomnia. On the other hand, eating more added sugar, starch, refined grains, and a high glycemic index diet (diet of foods that raise your blood sugar quickly) was linked with higher odds of insomnia.
American Journal of Clinical Nutrition. 2020 Feb 1;111(2):429-439. doi: 10.1093/ajcn/nqz275. (Gangwisch JE et al.)

Healthy menu items are seemingly easier to find at restaurants than they were ten years ago, but are people actually eating these dishes? To find out, researchers analyzed the nutritional content of fast-food and full-service restaurant dishes eaten by 35,015 adults between 2003 and 2016. Although the overall diet quality remained poor for both fast-food and full-service restaurant meals eaten by the participants, there are a few promising signs of progress. Notably, whole grains eaten at restaurants increased from 0.22 to 0.49 servings per day in full-service restaurants, and 0.08 to 0.31 servings in fast food restaurants. There were also slight increases in nut/seed/legume intake at fast food restaurants, as well as slight decreases in soda consumption at full-service restaurants and saturated fat and sodium consumption at fast food restaurants. Unfortunately, over this time period, people also at fewer fruits and vegetables at both types of restaurants, and the nutritional disparities between different racial and ethnic demographic groups persisted and, in some cases, worsened.
Journal of Nutrition. 2020 Jan 29. pii: nxz299. doi: 10.1093/jn/nxz299. [Epub ahead of print] (Liu J et al.)

The Mediterranean diet is well-known for its links to brain health, and new research demonstrates that these ties hold up in populations with heart disease as well. In this study, researchers analyzed the diets of 200 men (average age 57), then assessed their brain health 14 and 20 years later. Not following a Mediterranean Diet was linked with a greater decline in overall cognitive performance and visual spatial functions.
Nutritional Neuroscience. 2020 Jan 22:1-9. doi: 10.1080/1028415X.2020.1715049. (Lutski M et al.)

While some headlines focus on the supposed benefits of choosing a low-carb or a low-fat diet, the smarter dietary move is to focus on overall diet quality, and let the numbers fall where they may. In this study, researchers analyzed the food choices of 37,233 US adults, then followed them for years to see if diet impacted risk of death. Neither low-carb nor low-fat diets were linked with death. However, when differentiating between healthy and unhealthy diets, both unhealthy low-carb and low-fat diets were linked with increased mortality risk over the study period, while healthy low-carb and low-fat diets were both linked with lower risk of mortality over the study period. Therefore, it seems that the amount of fat or carbs is less important than the quality of fat or carbs.
JAMA Internal Medicine. 2020 Jan 21. doi: 10.1001/jamainternmed.2019.6980. [Epub ahead of print] (Shan Z et al.)

Olive oil is famously healthy due in part to its polyphenol content, and researchers wonder if cooking the olive oil degrades any of its nutritional properties. In this study, research tested the phenolic content of olive oil after sautéing it at medium (about 250°F) and high (about 340°F) temperatures on the stovetop over various periods of time (15-60 minutes) to replicate home cooking. They found that temperature had a much bigger impact than time, and that cooking at a medium temperature on the stovetop decreased polyphenol content by 40%, and that cooking at a high temperature on the stovetop decreased polyphenol content by 75%. Nonetheless, they found that cooked olive oil still meets the parameters of the EU’s health claim, as it still has the level of polyphenols necessary to prevent LDL oxidation. (LDL oxidation is the creation of a dangerous type of cholesterol that can clog arteries).
Antioxidants. 2020 Jan 16;9(1). pii: E77. doi: 10.3390/antiox9010077. (Lozano-Castellón J et al.)