We know that nutrients that are added to fortify foods get absorbed because fortification programs work. When we started added folic acid to flour and cereal, for example, the incidence of birth defects like spinal bifida—which is caused by folic acid deficiency—went way down. Likewise, the introduction of iodized salt drastically reduced the number of people walking around with goiters, which are caused by iodine deficiency. Fortifying milk with vitamin D made rickets largely obsolete. That’s not to say that fortification programs are perfect or that they never have unintended consequences. But that’s a subject for a different article!
Likewise, when people take vitamin supplements, you can usually measure an increase in the level of nutrients in their blood and tissues. But it’s also not uncommon for nutrients to spill over into the urine, especially if the supplements contain doses that are simply higher than the body can absorb or use. For example, when you take calcium supplements, you excrete more calcium, but that doesn’t mean you’re not absorbing any calcium. You’re just not absorbing all of it.
Supplements have their place, and I’ve talked about the role of multivitamins and other nutrients in previous articles.
Organic farming also provides a convenient contrast to conventional agricultural practices. A review by The Organic Center of 97 published studies comparing organic and conventionally grown food indicated that “on average” organic foods are more nutritious than conventional foods.[20] Conventional foods often contained more macro nutrients – potassium, phosphorus, and total protein – but organic foods were consistently and significantly higher in Vitamin C, Vitamin E, polyphenols, and total antioxidants, which are frequently lacking in American diets. Farms can be certified as organic after refraining from use of inorganic fertilizers and pesticides for only three years. It may take decades of organic farming to fully restore the chemical and biological health of “worn out” soils.
The blame for obesity also is often placed on the prevalence of highly processed foods and fast foods. Obviously, food processing and distribution deserve a share of the blame. The large corporations are not concerned about diet or health, unless it affects their profits. During the past 30 years, high-fructose corn syrup has replaced cane and beet sugar as the sweetener of choice because it has been cheaper. The growing popularity of carbonated beverages has meant increased consumption of high-fructose corn syrup.[21] Soybean oil, particularly partially-hydrogenated vegetable oil, has replaced lard and butter as the fat of choice, at least partially because it has been cheaper. Vegetable oils have found a growth market in the deep fryers of the fast food industry. In fact a significant portion of increased calorie consumption has resulted from increased spending for food eaten away form home. In recent years, about half of all food purchases are for foods eaten outside the home, about half of which are fast foods.
Best-selling books, such as Fast Food Nation[22] and Omnivore’s Dilemma,[23] document the negative consequences of fast foods and processed foods. Fast food franchises that have thrived economically by selling large portions of foods, high in sweets, fats, and salt, are coming under increased public scrutiny by public health officials. Low income consumers also are lured to the isles of supermarkets filled with low-priced, high-calorie food choices. Food industry marketers know that humans have a natural taste preference, probably a genetic predisposition, for foods that are high in fat, sugar, and salt. Preferences essential for the survival and health of our primitive ancestors now make us vulnerable to economic exploitation. It’s easier to market high calorie foods, particularly when those foods are cheaper. There is little doubt that processed foods and fast foods are contributing to the problem of obesity.
However, highly processed foods, fast foods, and sedentary lifestyles obviously aren’t the only significant factors contributing to obesity. Numerous studies have shown significant reductions in nutrient density of crops at the farm level with increasing use of modern yield-enhancing technologies – fertilizers, pesticides, high plant density, and irrigation.[24] This so called “dilution effect” apparently is well known among plant scientists, although rarely mentioned in relation to diet and health outside of organic circles.[25] The Albrecht hypothesis linking soil health directly to human health remains largely unexplored.
This is the most basic level of protein folding, and consists of a few basic motifs that are found in all proteins. The secondary structure is held together by hydrogen bonds between the carboxyl groups and the amino groups in the polypeptide backbone. The two most common secondary structure motifs are the 
