Читать книгу Textbook of Lifestyle Medicine - Labros S. Sidossis - Страница 87

The interest in the metabolic effect of food ingredients on the human body dates back to the nineteenth century. In his lecture “Disorders resulting from defective nutriment” given in 1842, George Budd noted, “There is no subject of more interest to the physiologist or of more practical importance to the physician … than the disorders resulting from defective nourishment.”

In the first half of the twentieth century, scientists extensively studied the effects of single nutrients, mainly vitamins and minerals, on the development of various diseases. This perspective led into a new era in nutritional science and provided a myriad of scientifically based evidence on the effect of macro‐ or micronutrients deficiency or surplus on disease development. An example of a disease caused by a single nutrient deficiency is that of scurvy. Scurvy develops due to ascorbic acid deficiency, and it is accompanied by fatigue, lethargy, and malaise, in the early stages, and myalgia, anemia, depression, poor wound healing, and even death in late stages (Figure 5.1a and b). It is noteworthy that scurvy was the focus of what is considered to be the first controlled clinical trial. Specifically, in 1747, during his service as a physician at the British Royal Navy, James Lind studied the effect of citrus fruits (lemons and oranges) in the treatment of scurvy in British sailors. He noticed that the group allocated to including lemons and oranges in their diet showed significant improvement within a week, while those who didn't receive lemons and oranges did not recover even after 2 weeks.

Furthermore, back in the 1880s, the industrialization of milling was established and the refinement of grains became a common practice, as it increased the storage life of the grains. During the refinement process, the bran and the sperm are removed and hence, B‐complex vitamins, fibers, and PUFAs are also removed. Soon, pellagra and beriberi epidemics appeared for the first time. In pellagra, the parts of the body exposed to sunlight suffer from dermatitis, but there are also mental and gastrointestinal implications. Using epidemiologic methods, scientists determined that pellagra was a disease of nutritional deficiency common in people who obtain most of their food energy from maize, notably rural South America, where maize is a staple food.

FIGURE 5.1 Perifollicular hemorrhages on both legs (a) and ecchymosis (b) are classic skin findings of scurvy.

Source: Reprinted from Lipner (2018): 431.

There are two types of beriberi – wet beriberi, which affects the cardiovascular system, and dry beriberi, which affects the nervous system. Around 1937, scientists detected that the lack of niacin (vitamin B₃) and thiamin (vitamin B₁) caused pellagra and beriberi, respectively.

In the last few decades, newly discovered food constituents have been shown to affect human health. For example, there is now considerable scientific evidence suggesting that plant polyphenols, which belong to the large group of phytochemicals, may account for some of the reported anti‐carcinogenic and cardioprotective effects of plant foods. On the other hand, polyphenols, like flavonoids and lignans, have been associated with decreased risk for the development of CVDs. Two other polyphenolic classes, flavonols and flavones, have been shown to decrease mortality rate and prevent fatal and nonfatal coronary artery disease.

Even though it is now generally accepted that several nutrients have positive health effects, people do not consume single nutrients; they consume foods. And foods consist of many different nutrients in heterogeneous proportions.