Vitamin chronic disease prevention

Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults scientific review. JAMA 2002 287(23) 3116-26. 

Traber, M.G. Frei, B. Beckman, J.S. 2008. Vitamin E revisited do new data validate benefits for chronic disease prevention Curr. Opin. Lipidol. 19 30-38. 

In the Unites States, the daily intake of 3-carotene is around 2 mg/day Several epidemiological studies have reported that consumption of carotenoid-rich foods is associated with reduced risks of certain chronic diseases such as cancers, cardiovascular disease, and age-related macular degeneration. These preventive effects of carotenoids may be related to their major function as vitamin A precursors and/or their actions as antioxidants, modulators of the immune response, and inducers of gap-junction communications. Not all carotenoids exert similar protective effects against specific diseases. By reason of the potential use of carotenoids as natural food colorants and/or for their health-promoting effects, research has focused on better understanding how they are absorbed by and metabolized in the human body. 

Vitamins B12 and B6 have preventive effects against age-related chronic diseases, including cardiovascular disease (CVD), stroke, and cognitive decline... 

Nutrients are the constituents of food necessary to sustain the normal functions of the body. All energy is provided by three classes of nutrients fefe, carbohydrates, protein, and in some diets, ethanol (Figure 27.1). The intake of these energy-rich molecules is larger than that of the other dietary nutrients. Therefore, they are called the macronutrients. This chapter focuses on the kinds and amounts of macronutrients that are needed to maintain optimal health and prevent chronic disease in adults. Those nutrients needed in lesser amounts, such as vitamins and minerals, are called the micronutrients, and are considered in Chapter 28. 

Vitamin E is not recommended for the prevention of chronic disease, such as coronary heart disease or cancer. Clinical trials using vita min E supplementation have been uniformly disappointing. For example, subjects in the Alpha-Tocopherol, Beta Carotene Cancer Prevention Study trial who received high doses of vitamin E, not only lacked cadiovascular benefit but also had an increased inci dence of stroke. 

Carotenoids, a class of yellow to deep-red pigments present in many commonly eaten fruits and vegetables, have been hypothesized to play a role in the prevention of chronic diseases such as cancer and heart disease. Most research to date has focused on the relationship between P-carotene and lung cancer. Lung cancer is one of the most common cancers in the U.S., and P-carotene was initially the most thoroughly studied carotenoid because of its role as a vitamin A precursor (Cooper et al., 1999). 

The biological activities of carotenoids, such as (3-carotene, are related to their provitamin A activity within the body (Clinton, 1998). Since lycopene lacks the (3-ionic ring structure, it does not have any provitamin A activity (Stahl and Sies, 1996). The biological effects of lycopene in humans have therefore been attributed to mechanisms other than vitamin A. Two major hypotheses have been proposed to explain the anticarcinogenic and antiatherogenic activities of lycopene oxidative and nonoxidative mechanisms. The proposed mechanisms for the role of lycopene in the prevention of chronic diseases are summarized in Figure 6. 

Food fortification and designer foods specially formulated to prevent chronic diseases are enthusiastically advocated by the vitamin industry and its proponents (16). Unrestrained vitamin fortification added to unrestrained supplementation with these substances has now in some countries led to the potential for rather high cumulative amounts of intake in some populations. There is growing concern about the safety of chronically high doses of some of these, where the therapeutic margin between deficiency and toxicity may not be all that wide (15,17-19). 

Ascorbic acid, a water-soluble vitamin (1(X) to 250 mg p.o. daily), is indicated in the treatment of frank and subclinical scurvy in extensive bums, delayed fracture or wound healing, postoperative wound healing severe febrile or chronic disease states and in prevention of ascorbic acid deficiency in those with poor nutritional habits or increased requirements. In addition, ascorbic acid has been used for potentiation of meth-enamine in urine acidification and as an adjunctive therapy in the treatment of idiopathic methemoglobinemia. 

Vitamin. Bg helps in the production of serotonin from the amino acid known as L-tryptophan. Some research suggests that B6 might help address premenstrual syndrome (PMS), autism, and some seizure disorders, as well as help prevent many chronic diseases associated with inflammation. A study also found that supplementation helped antidepressants work better in an elderly population who also had cognitive dysfunction. I recommend 10 to 50 mg twice a day of the pyridoxal-5-phosphate (or pyridoxine ), the active form of Bg. Ideally, you should take the dosage between meals, but if it causes nausea, take it with food. Be careful not to exceed the recommended dose, particularly because doses over 300 mg daily may lead to peripheral neuropathy (numbness and tingling in the hands and feet). 

Table 3.1 Folic acid, Bg, B12 and cardiovascular outcomes. This table summarizes all the important double-blind randomized clinical trials with the use of folie acid, Bg and B12 vitamins for cardiovascular disease prevention. 5-MTHF 5-methyl tetrahydrofolate CKD chronic kidney disease CVD cardiovascular disease DVT deep vein thrombosis ESRD end stage renal disease FA folic acid f/u follow-up MI myocardial infarction RR relative risk UA unstable angina.

Vitamin deficiency. This is the lack of vitamins in the organism in the adequate amount. Vitamins are compounds that caimot be synthesized by humans and therefore must be ingested to prevent metabohc disorders. Inadequate intake or subtle defieiencies in several vitamins are risk factors for chronic diseases such as cardiovascular disease, cancer and osteoporosis. 

The epidemiological data on vitamin C have not reached the stage where we can assign vitamin C a pivotal role in the prevention of chronic diseases. With respect to a causal relationship based on epidemiological evidence, there is a lack of specificity and agreement between the different study approaches. However, there is a high level of biological plausibility, and there are, in some areas, consistent... 

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