Search Health Studies

Eating More Fruits and Vegetables Can Help You Lose Weight

Science and common sense tell us that eating a wide variety of fruits and vegetables is one of the best defenses against obesity and weight gain. To quantify this relationship, Harvard researchers analyzed the eating patterns and weight changes in over 130,000 adults for over 20 years. Eating vegetables of all kinds was linked to a 0.25 pound weight loss per daily serving over four years, while eating fruit of any kind was linked to a 0.53 pound weight loss per daily serving over four years. Upon closer inspection, they found that this relationship was strongest for berries, apples, pears, tofu, soy, cauliflower, and cruciferous and green leafy vegetables. On the other hand, starchy vegetables like peas, corn, and potatoes were associated with weight gain. The researchers concluded that these “findings support benefits of increased fruit and vegetable consumption for preventing long-term weight gain.”
PLOS Medicine. 2015 Sept 22. [Epub] (Bertoia ML et al.)

Med Diet Plus Exercise May Prevent Eye Disease

Age related macular degeneration (AMD) is the leading cause of vision loss in older adults, mostly occurring in those over 60 years old. To see if eating patterns play a role in this disease, researchers analyzed the diet of nearly 900 Portuguese adults (ages 55+), half with AMD, and half without. Those without AMD ate foods more closely aligned with the Mediterranean diet (grains, green leafy vegetables, fruit, and olive oil) than those who did have AMD. The group without AMD also exercised more, and ate less fast food, meat, dairy, and ready-made meals. This study suggests that a Mediterranean style diet, along with exercise, may be protective against AMD.
Presentation at the European Society of Retina Specialists 15th EURETINA Congress. Nice, France. September 17, 2015. (Farina C et al.)

Mediterranean Diet May Lower Breast Cancer Risk by Over Half

With incidence of breast cancer increasing in recent years, lifestyle and prevention measures are more important than ever. Using data from the PREDIMED study (where adults at risk for heart disease were assigned to either a low fat diet, a Mediterranean diet with olive oil, or a Mediterranean diet with nuts), scientists analyzed the eating patterns and health outcomes of over 4,200 women (ages 60-80). During the 5-year follow up period, 35 women developed breast cancer.  Those in the Mediterranean diet groups were 51% less likely to get breast cancer than those on a low-fat diet. The Mediterranean diet with olive oil group was 62% less likely to get breast cancer, while the Mediterranean diet group with nuts had a non-significant lower risk of breast cancer.
JAMA Internal Medicine. 2015 Sep 14:1-9. [Epub ahead of print.] (Toledo E et al.)

Beans Just as Filling as Meat

Pulses, the food group that includes beans, peas, chickpeas, and lentils, are central to traditional cuisines around the world, and are an especially important source of nutrients in plant-based diets. In a small study, researchers at the University of Minnesota fed 28 adults either a bean-based “meatloaf” (17g protein, 12g fiber) or a beef-based meatloaf (26g protein, 3g fiber) to compare how beans and meat affect fullness. The two meals had equal calories, fat, and weight. One week later, the adults changed groups and were given the other meatloaf, serving as their own control. The scientists found no significant differences in appetite or food intake at the next meal between the two different meatloaves, suggesting that beans are just as satiating as beef, possibly due to their fiber and protein content. However, the bean group did experience moderate gas and bloating.
Journal of Food Science. 2015 Sep;80(9):2088-93. (Bonnema AL et al.)

Med Diet with Olive Oil May Prevent Diabetic Eye Damage

Complications from diabetes can lead to serious health problems, including vision impairment, blindness, and kidney damage. Using data from the PREDIMED study (where adults at risk for heart disease were assigned to either a low fat diet, a Mediterranean diet with olive oil, or a Mediterranean diet with nuts), researchers analyzed data from over 3,600 Spanish adults with type 2 diabetes, to see how diet affects the risk of diabetic nephropathy (kidney damage from diabetes) or diabetic retinopathy (eye damage from diabetes). Those following a Mediterranean diet with olive oil had a 43% lower risk of diabetic retinopathy compared to the low fat control group, and those following a Mediterranean diet with nuts had a non-significant 38% lower risk of diabetic retinopathy. There were no significant changes in the risk for diabetic nephropathy.
Diabetes Care. 2015 Sept 13. [Epub ahead of print] (Diaz-Lopez A et al.)

Eating Fish May Prevent Depression

Fish is well known for its place in many of the healthiest diets around the world. To determine the link between eating fish and depression risk, Chinese scientists reviewed 26 studies of over 150,000 people. The researchers concluded that “high fish consumption can reduce the risk of depression.”  
Journal of Epidemiology and Community Health. 2015 Sep 10. pii: jech-2015-206278. [Epub ahead of print.] (Li Fu et al.)

Lower Birth Defects Linked with Moms Who Eat Healthy Med Diets

Congenital heart defects (heart problems that occur before birth) affect nearly 1% of newborns in America. In a study of over 19,000 American women, researchers compared mothers of babies with congenital heart defects to mothers of babies without this condition. Scientists analyzed the mothers’ diets in the year before pregnancy using both the Mediterranean Diet Score and the Diet Quality Index for Pregnancy. Babies whose moms’ diets ranked healthy on both scores were significantly less likely to suffer from certain specific subgroups of congenital heart defects, such as tetralogy of Fallot (a defect in heart structure which causes oxygen poor blood to flow throughout the body), but not all heart defects. The relationship between diet and congenital heart defects was stronger with the Diet Quality Index for Pregnancy than with the Mediterranean Diet.
Archives of Disease in Childhood. Fetal and Neonatal Edition. 2015 August 24. pii: fetalneonatal-2014-308013. [Epub ahead of print.] (Botto LD et al.) 

Whole Grains Offer Benefits Beyond Fiber

Whole grains are well known for their fiber; however, fiber is not the only benefit of a diet rich in whole grains. This study uses nutritional metabolomics (a field of that looks at how different foods affect metabolism) to explore how the different compounds in whole grains may affect metabolism, and suggests scientific reasons behind the health benefits of whole grains, beyond just their fiber content. Specifically, this analysis suggests that whole grains may have positive effects on insulin sensitivity and protein metabolism, and may contain other beneficial compounds, such as glycine betaine.
Proceedings of the Nutrition Society. 2015 Aug;74(3):320-7. doi: 10.1017/S0029665114001542. Epub 2014 Oct 23. (Ross AB et al.)

Switching to Mediterranean Fat Sources May Help Inflammation

Palmitic acid (found in palm oil, shortening, butter, and red meat) is a type of saturated fat prevalent in the Western diet, while oleic acid (found in olive oil) is a type of monounsaturated fat prevalent in the Mediterranean diet. In a small study, researchers at the University of Vermont fed 16 adults either a diet high in palmitic acid or a diet high in oleic acid and low in palmitic acid to see how food choices affect the inflammatory response of various cells. All adults spent 3 weeks in each diet group, serving as their own control.  Although insulin sensitivity was not affected in this experiment, the scientists found that changing the diet to include more oleic acid and less palmitic acid was able to lower activation of certain cell signaling proteins (including TLR4 and NLRP3) that are associated with inflammation, oxidation and poor insulin signaling. These results suggest that shifting from a Western diet to a Mediterranean style diet (with greater proportions of oleic acid) may help fight inflammation.
Journal of Nutritional Biochemistry. 2015 Aug 1. pii: S0955-2863(15)00178-3. (Kien CL et al.)

Mediterranean Meals with Olive Oil Can Improve Blood Sugar Control, Cholesterol

In a small Italian study, researchers assigned 25 healthy adults to a Mediterranean meal (pasta, chicken breast, salad, bread, and an apple) prepared either with or without olive oil, then measured their cholesterol and blood sugar. After 30 days, the participants switched groups and ate the other meal, serving as their own control. The scientists found that 2 hours after eating, the meal without olive oil was associated with higher glucose and insulin levels, as well as higher “bad cholesterol” (LDL-C). In the second part of the experiment, the participants were assigned to a Mediterranean meal prepared with either olive oil or corn oil, switching groups after a 30 day washout period. Their blood sugar and cholesterol was tested after the meals as well. Two hours after eating, the meals with olive oil were associated with a lower increase in blood sugar and improved markers of blood sugar control (such as lower DPP, and higher GLP1 & GIP), as well as a smaller increase in “bad cholesterol” (LDL-C and oxidized LDL). These experiments indicate that meals with olive oil can help regulate blood sugar, and may help improve cholesterol.
Nutrition & Diabetes. 2015 July 20;5:e172. [Epub ahead of print.] (Violi F et al.)

Vegetarian Diets Linked with More Calorie Burning

Weight is thought to be managed largely by balancing calories eaten with calories burned, so researchers are studying why some people tend to burn calories more easily than others. In an Italian study, researchers recruited 52 adults (half vegetarian, half not) and matched each group by age, BMI, and gender. All of the vegetarians had been following their diet for at least 3 years. After adjusting for age, BMI, exercise, and other lifestyle factors, the scientists found that the vegetarians had a significantly higher resting energy expenditure, meaning that their bodies burned more calories at rest. Of the different dietary components studied, higher intake of vegetable fats (oils, nuts, seeds) were most closely associated with the significantly higher resting energy expenditure seen in vegetarians. 
Nutrients. 2015 Jul 17;7(7):5933-47. (Montalcini T et al.)

 

Whole Plant Foods, Not Specific Nutrient Profiles, Best for Heart Disease Risk

Evidence is mounting that the healthiest diets are built around a variety of minimally processed, whole foods, and can’t be reduced to specific nutrients. To determine saturated fat’s role in heart disease risk, researchers from California reviewed the existing literature about saturated fats, polyunsaturated fats, carbohydrates, and heart disease. The scientists found that when saturated fat (found mostly in red meat and milk fat) is replaced with polyunsaturated fat (found mostly in nuts, seeds, and fish), heart disease risk decreases. However, when saturated fat is replaced with sugary refined carbohydrates, heart disease risk remains the same, if not worsens. The researchers also note a small, yet growing body of research that dairy fat (especially in fermented dairy, like yogurt), may be neutral (or even decrease risk) for heart disease. The researchers concluded that “overall dietary patterns emphasizing vegetables, fish, nuts, and whole versus processed grains form the basis of heart-healthy eating, and should supersede a focus on macronutrient composition.”
Annual Review of Nutrition. 2015 July 17;35:517-43. (Siri-Tarino PW et al.) [Epub]

Pages