Avocados are widely regarded as healthy food

Does science agree?

The Haas Avocado Board in California commissioned a study of the nutrient composition of avocados and the potential health effects of those nutrients. Avocados contain a wide variety of nutrients including fiber, minerals, vitamins, and phytochemicals. Two nutrients are especially noteworthy: 1) high abundance of mono-unsaturated fatty acids, primarily oleic acid, and 2) dietary fiber, mostly insoluble. Half of an avocado provides about one-sixth of recommended daily fiber intake. The fatty acid-water matrix of these fruits appears to increase nutrient availability. Water and insoluble fiber comprise nearly 80 percent of avocados’ edible weight. Thus, avocados fall in the medium energy-density range. Even though avocados contain considerable fat, studies suggest that avocados do not impede attempts to lose weight. Unlike most fruits, avocados contain minimal sugar. Several studies suggest that avocados beneficially affect blood fats consistent with better heart health.

Given that avocados contain a variety of nutrients, would eating avocados promote better health? Three nutrition consultants for the Hass Avocado Board used nationally representative, cross-sectional data from 17,567 adults in the National Health and Nutrition Examination Survey (NHANES) from 2001-2008 to see if avocado consumption was linked to various health measures. Food intake data came from 24-hour dietary recalls, while diet quality was determined using the USDA Healthy Eating Index - 2005.

Only about 2 percent (347 people) of the participants reported eating avocados, with an average daily intake of one-half of an avocado per person. Compared to participants who did not eat avocados, those who did had significantly better Healthy Eating Index – 2005 scores, along with greater intake of fruits and vegetables and lower intake of added sugar. In addition, compared to participants who did not eat avocados, those who ate avocados had significantly higher HDL-cholesterol intake (the “good” type), and lower body weight, waist circumference, and risk of the metabolic syndrome. Finally, participants who ate avocados had significantly higher intakes of total, monounsaturated, and polyunsaturated fat, fiber, vitamins E and K, minerals magnesium and potassium, and lower carbohydrate. Avocado consumption seems to be a marker for Eat Better.

Avocados contain nutrients that are linked to better cardiovascular health, including better blood fat profiles, lower blood pressure, blood glucose, insulin, body weight, and risk of the metabolic syndrome. A systematic review and meta-analysis that included 18 studies evaluated the evidence. The review found that higher avocado intake predicted significantly higher HDL-cholesterol concentrations. Higher HDL-cholesterol may reflect avocados’ high concentrations of monounsaturated fatty acids, plant sterols, and fiber. No significant links emerged between avocado intake and total cholesterol, LDL-cholesterol, triglycerides, ratio of total cholesterol to HDL-cholesterol, and body weight. That notwithstanding, higher avocado intake showed statistically non-significant improvements in the above factors; lack of statistical significance may have arisen from small sample sizes in the included studies.

Previous studies suggest that eating avocados might improve risk factors for cardiovascular disease, but long-term data were lacking. A new study rectified this shortcoming. Researchers at Harvard used data from 68,786 women in the Nurses’ Health Study and 41,701 men in the Health Professionals Follow-up Study to determine if avocado intake predicted lower risk of cardiovascular disease. Avocado intake data came from food-frequency questionnaires administered at baseline then every four years thereafter for up to 30 years.

After adjusting for lifestyle and dietary factors and compared to participants who did not report eating avocados, those who reported eating at least one avocado per week had 16 and 21 percent lower risks of developing cardiovascular disease and coronary heart disease, respectively, during median follow-ups of 13 and 14 years for men and women. Avocado intake did not predict decreased risk of stroke. Each one-fourth of an avocado increase in daily intake predicted a significant 21 percent decrease in risk of coronary heart disease. In addition, substituting half a serving of avocado per day (one-fourth of a fruit) for an equivalent amount of margarine, butter, egg, yogurt, cheese or processed meat predicted significant 11-22 percent lower risks of developing cardiovascular disease. This large, long-term prospective study provides the most compelling evidence to date of avocados’ high health value.

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