Diet, or what one consumes, affects health through a variety of biochemical processes that occur in the body once a food item is consumed. Since diet is in fact a multi-component mixture of a variety of nutrients that interact with each other, the pathways to health are complicated. Nonetheless, numerous studies have shown a strong association between dietary consumption patterns and health outcomes.
Diets rich in fruits and vegetables, fiber, and certain polyunsaturated or monounsaturated fats have been shown to be associated with a number of health benefits, particularly cardiovascular benefits.
Based on data from the Nurses' Health Study and Health Professionals Follow-up Study, which followed over a hundred thousand individuals over 14 years, increased daily intake of fruits and vegetables was associated with decreased risk of cardiovascular disease. In another study of the impact of fruits and vegetables on hypertension, individuals with high blood pressure who improved their intakes experienced reduced blood pressure, which would suggest obviating the need for medications. Lastly, fruit and vegetables consumption has been shown to lower LDL cholesterol.
Fiber, which is present in all plants foods, including fruits, vegetables, grains, and legumes, has been shown to be an important in the prevention of cardiovascular risks. Cereal fiber or the fiber in grains, in particular is beneficial in preventing heart disease. Fiber has also been shown to improve other factors that contribute to heart diseases, such as high blood pressure, blood insulin levels, abdominal fat, triglycerides, and HDL cholesterol. Diets high in levels of dietary fiber and foods that do not have a high glycemic index have also been associated with decreased risk of type 2 diabetes.
Fruits and vegetables may be associated with decreased risk of developing certain types of cancer. Vitamins found in fruits and vegetables are also important in preventing other health conditions such as cataracts or macular degeneration.
Nutritional values can be assessed in a number of ways, for instance, on a societal level the USDA has data that can: provide estimates of the average daily intake of food in the country; show annual changes in the consumption of major foods; provide insight about consumption trends, and can perform statistical analyses of price and income effects on food consumption. On an individual level, food journals, reading dietary labels and counting calories are some of the more common methods of measuring nutrition.
Downstream Health Effects
Dietary habits are associated with various health outcomes including type II diabetes, cardiovascular disease, mental health, and others.
Policies and Other Determinants
Nutrition policies can substantially affect food availability and food choices. Individuals can be encouraged though subsidies, programs, and policies to change purchasing and consumption behaviors. Examples of nutrition policies include:
- School Wellness Policies, in 2004 Congress passed a law requiring all school districts that receive federal funding for school meals to implement wellness policies that specifically address nutrition and physical activity. Meals must be attractive to children and must meet a minimum standard of fruit, vegetables, whole grains and low fat options
- Farmers Markets and Nutrition Advancement programs that increase access to and awareness of healthy and safe foods, are critical in promoting food and health literacy and availability to fresh produce, particularly in low SES communities
- Obesity Control programs promote the benefits of proper nutrition habits and exercise. Such programs are key in preventing or addressing the harmful effects of obesity, overweight and a host of other lifestyle related diseases