How Big is the Functional Need for GSH? Part 2
Because of the known functions and increased disease risk with a decline of GSH, systematic efforts are needed to quantify the difference between the available GSH and the amount needed. One approach is to consider how much GSH is present in a natural diet. GSH content has been measured in more than 100 common foods37 and provides the basis to estimate dietary intake. The best diets contain about 150 milligrams of GSH per day; the worst diets contain as little as 3 milligrams per day. GSH is present in essentially all raw and freshly prepared foods; the best sources are fresh fruits and vegetables, nuts, and whole-cut meats, including poultry and fish. GSH can also be increased by supplements, such as the increase in hepatic GSH following ingestion of silymarin, found in milk thistle. GSH is lost during most food processing procedures, with the exception of fresh-frozen foods. Processed, cured, and canned meat products have essentially no GSH. Similarly, canned or dried fruits and canned vegetables are not good sources. Cereal and grain products are largely deficient, and almost all dairy products, beverages, sweeteners, and condiments lack GSH. Thus, a simple conclusion is that modern processed foods are deficient in GSH compared to natural, freshly prepared foods. In quantitative terms, up to 150 mg of daily intake of GSH can be lost due to food processing.
Many foods also contain reactive chemicals that remove GSH through the GSH transferase reaction associated with the lining of the small intestines. Measurement of a broad range of foods show that milk, prunes, tea, blueberries, and bottled apple juice have high contents of GSH-reactive chemicals.38 Recently, there has been interest in the potent neurotoxicant acrylamide, because this has been found to be relatively high in french fries. The daily intake of GSH-reactive equivalents can range from almost zero to values exceeding the maximum naturally available 150 milligrams GSH.38 Thus, the sum of the amount of GSH needed to eliminate reactive chemicals and the amount of GSH lost by food processing can be greater than 300 mg of GSH per day.
Discount ed meds
Measurement of a broad range of foods show that milk, prunes, tea, blueberries, and bottled apple juice have high contents of GSH-reactive chemicals.
The extent to which environmental exposures, alcohol consumption, smoking, inflammation, infection, etc., further increases this dietary GSH gap is not known. Similarly, the magnitude of the GSH gap due to disease is not known. This could be greater than 300 mg—perhaps as high as the GSH equivalent of the RDA for sulfur amino acids (ie, 3 g/day). The RDA for sulfur amino acids is about 1.1 g/day for women and 1.4 g/day for men; these values are equivalent to 2.7 and 3.3 g/day of GSH. Because the body contains 15 g of GSH, values in this range represent up to 20% of the amount of GSH in the body. There are conditions, such as severe burns, in which the sulfur amino acid requirement is increased. Consequently, there may be conditions in which the functional need for GSH is relatively high, but this upper limit is currently unknown.