A year later, a second Harvard study added to the concern. The Physicians' Health Study of 20,885 men did not evaluate diet per se, but it did measure the blood levels of ALA in 120 men who developed prostate cancer and compared them with the levels in 120 men who remained free of the disease. Men with moderately high ALA blood levels were 3.4 times more likely to develop prostate cancer than men with the lowest levels; curiously, though, men with the very highest levels were only 2 times more likely to get the disease.
Carbohydrates should provide 45%–65% of your daily calories. Most of those calories should come from the complex carbohydrates in high-fiber and unrefined foods, such as bran cereal and other whole-grain products, brown rice, beans and other legumes, and many fruits and vegetables. These carbohydrates are digested and absorbed slowly, so they raise the blood sugar gradually and don't trigger a large release of insulin. People who eat lots of these foods have higher HDL ("good") cholesterol levels and a lower risk of obesity, diabetes, and heart disease. A good amount of soluble fiber in the diet lowers LDL ("bad") cholesterol, and high-fiber diets reduce the risk of intestinal disorders ranging from constipation and diverticulosis to hemorrhoids. Some studies have shown that fiber may help reduce the risk of colon cancer. Men need more fiber than women: 38 vs. 25 grams a day before the age of 50 and 30 vs. 21 grams a day thereafter.
Iodine is needed for normal mental development of the baby, but it can be difficult to get enough from food. Ways of increasing iodine intake include using iodised salt, eating fish and seafood weekly (see your health professional for advice about safe types and amounts of fish), or using a multivitamin supplement that contains iodine and is safe for pregnancy.
Choline: Some studies link low choline levels to increased risk of neural tube defects. Recommended levels have been established for this nutrient, but it's easy to get enough in your diet. Eggs are an excellent source of choline, for example. “Eating a few eggs a week should give you all you need,” Frechman says. “Most people can eat the equivalent of an egg a day without worrying about cholesterol.” Other choline-rich food sources include milks, liver, and peanuts.
Studies link high sodium intake to higher blood pressure, and evidence suggests that many people at risk for high blood pressure can reduce their risk by consuming less salt or sodium, as well as following a healthy diet. Most Americans consume more sodium than they need. The recommended amount is less than 2,300 mg per day for children and adults to age 50. The limit drops to 1,500 mg per day for those 51 and older or those of any age who are African American or have hypertension, diabetes or chronic kidney disease. You get 2,300 mg in just one teaspoon of salt. One good way to reduce your sodium intake is to eat fewer prepared and packaged foods.
For girls and adult women, educational interventions are considered a powerful means of improving their health and nutritional status throughout their lives. Education level is often associated with maternal caregiving practices and the nutritional outcomes of their children (174, 175). Few studies, however, evaluated the impact of education as an intervention on women's nutrition outcomes. Instead, many studies used survey data and reported on associations between education and nutrition. For instance, in low- and middle-income countries, higher levels of education were associated with lower prevalence of underweight and higher prevalence of overweight among women (176, 177). However, this depended on the type of employment in which women participated (178, 179). In addition, in many high-income settings, the converse was true (177). Level of literacy was also associated with improved anthropometric measures. In southern Ethiopia, literate mothers were 25% less likely to be undernourished than were illiterate women (180). One econometric analysis suggested that doubling primary school attendance in settings with low school attendance was associated with a 20–25% decrease in food insecurity (181). Overall, though, these associations were limited in their ability to draw conclusions about causality and the effect of education interventions on nutrition outcomes.