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Dietary Sources of Calcium and Supplements

Calcium is abundant in plant foods, such as almonds, fresh and dried fruits, seeds, and a wide assortment of vegetables, particularly low-oxalate greens (bok choy, broccoli, dandelion greens, kale, mustard greens, napa cabbage, turnip greens, and watercress). A lesson can be learned from big-boned animals, such as cows and elephants, who graze on greens in a leisurely manner every day, consuming large amounts. The low-oxalate greens bok choy, broccoli, and kale contain calcium that is extremely well absorbed by our bodies in the range of 40–61 percent (compared to absorption rates of 30–32 percent from cow’s milk and tofu). From high-oxalate greens (such as beet greens, spinach, and Swiss chard) and rhubarb, we absorb only 5–8 percent of the calcium present.45

One farmer says to me, “You cannot live on vegetable food solely, for it furnishes nothing to make bones with,” and so he religiously devotes a part of his day to supplying his system with the raw material of bones; walking all the while he talks behind his oxen, which, with vegetable-made bones, jerk him and his lumbering plough along in spite of every obstacle.

 

HENRY DAVID THOREAU,
Walden, 1852

 

While we can get 1,000 milligrams of calcium from eleven cups of kale (and absorb it even better than calcium from cow’s milk), that is a lot of kale to consume! Another way we might choose to get our day’s supply of calcium is from three oranges, a very large salad (three cups each of kale, napa cabbage, and romaine lettuce), three tablespoons of sesame tahini (in salad dressing), one-half cup of almonds, plus five figs. Typically, a wide assortment of raw plant foods contributes to our overall mineral intake, and we can meet our needs in a vast number of tasty ways. (See the menus in chapter 12, pages 244–249.) For calcium sources in raw diets, see table 9.4, page 198.

Calcium supplements can be a wise choice to top up your intake, if you have difficulty consuming enough calcium from foods. No multivitamin-mineral tablet contains 100 percent of the DRI (or DV, for daily value) for calcium; the resulting pill would be too large to swallow. Calcium preparations used as supplements include calcium carbonate, calcium citrate, calcium citrate malate, calcium gluconate, and calcium lactate. To maximize absorption, use a supplement that includes vitamin D. Most calcium supplements should be taken with meals, although calcium citrate and calcium citrate malate can be taken anytime.37, 83

CHROMIUM

Raw Research and Functions

Chromium supports the action of the hormone insulin. Without sufficient chromium, syndrome X (also known as metabolic syndrome) can develop, a condition that combines symptoms of insulin resistance, obesity, high blood pressure, high LDL (“bad” cholesterol), high triglycerides, and low HDL (“good” cholesterol). When carbohydrates are refined in the production of white flour and sugar, one of the minerals that is lost is chromium; consequently, it is reasonable to place at least part of the blame for syndrome X on diets that are high in refined carbohydrates. High intakes of glucose and fructose (found in agave syrup and honey) as well as sucrose can deplete chromium.69, 84 The DRI for chromium for men is 35 micrograms to age 50 years, and 30 micrograms after that; for women it is 25 micrograms to age 50 years, and 20 micrograms after that. Requirements of athletes may be slightly higher than those of nonathletes.69

Dietary Sources of Chromium

Chromium is present in nuts, seeds, fruits, vegetables, and sea vegetables. Data showing specific quantities of chromium in foods is very limited and unreliable, and amounts reported for particular foods can vary widely. One reason for the lack of accurate data is that chromium contamination can occur when samples are tested. Also, the amounts in soil vary greatly from one geographical region to another. Nonetheless, a raw diet that meets caloric requirements and is centered on whole plant foods can be expected to provide reasonable amounts of chromium.69

COPPER

Raw Research and Functions

Copper intakes of raw foodists, vegans, and other vegetarians tend to meet the DRIs shown in table 9.2, page 185, and are usually higher than those of nonvegetarians. Copper is an integral part of the enzymes that are involved in the utilization of iron, in protecting us from free radicals, and in protein metabolism. It is also used for building connective tissue, bones, and hormones.

Dietary Sources of Copper

We need not worry about copper, as we can meet the DRIs with a daily handful of nuts and seeds. Copper is abundant in Brazil nuts, pecans, other nuts, seeds, sweet potatoes, and fruits, such as bananas, raisins, and prunes (see table 9.4, page 198). High intakes of zinc (for example, when someone consumes zinc as a single mineral supplement in excess of the DRI) can prevent the absorption of copper, resulting in copper deficiency. This problem does not occur with use of a multivitamin-mineral supplement.36, 69, 85

IODINE

Raw Research

Iodine is of particular interest to those on raw diets. The recommended intake for adults is 150 micrograms (mcg) of iodine per day, a miniscule amount. However, raw and vegan diets can miss the mark and hit two extremes, with some falling short and others with iodine intakes that are excessive. Finns who had followed living-food diets for three to ten and a half years had iodine intakes (shown in table 9.2) that clustered in two groups: one group had low average intakes of 29 micrograms per day, and the other group, whose sea vegetable intake was high, consumed 900 micrograms per day (which is below the acceptable upper limit, or UL, of 1,100 micrograms). One person also used iodized salt. Diets included moderate amounts of the substances from the cabbage family that can interfere with thyroid function (see page 190); about ¼ cup (30 grams) per day of sauerkraut was consumed. For Finns at both levels of iodine intake, their laboratory tests showed normal thyroid function.73–75, 86 Americans on the Hallelujah Acres diet included small amounts of kelp as an iodine source.72

Functions of Iodine

Iodine is a part of the thyroid hormones, and most of the organ systems in the body are under the influence of these hormones. Iodine is essential for energy metabolism, and deficiency can result in either depressed or accelerated metabolic function (also known as hypo- or hyperthyroidism, respectively). Insufficient iodine has been linked with fibrocystic breast disease. Iodine exerts its effect through the thyroid gland, which is located in the lower part of the throat. Hypothyroidism can result in a growth called a goiter, in which the thyroid gland becomes greatly enlarged in its efforts to trap iodine; other symptoms are skin problems, weight gain, and increased cholesterol levels, all of which can be reversed in adults with sufficient iodine in the diet.86, 87

Iodine intakes of some people on raw diets may be insufficient unless they use either iodized salt, supplements, or sea vegetables. Iodine deficiency is particularly risky during pregnancy, during which the DRI is increased to 220 micrograms.

 

Iodine deficiency during pregnancy is a different story, as this mineral is essential for normal brain development of the fetus. Its lack causes the most important and most easily preventable cause of mental retardation in children around the world—an irreversible and tragic condition known as cretinism. Thyroid hormones are crucial during pregnancy, while an infant’s brain is developing. Adults can survive severe iodine deficiency, but they cannot thrive or reproduce.85, 90–92

Iodine in Salt

Prior to the iodization of salt in 1924, goiter and cretinism appeared in many North American regions, such as the Great Lakes area and the Northwest. These conditions still occur in parts of Africa, Asia, Europe, and Latin America, where iodized salt is not used and where people eat locally grown foods with low iodine levels. In order to prevent goiter and cretinism, table salt has been fortified in many countries, so that about ⅜ to ½ teaspoon (2 milliliters) of iodized table salt or iodized sea salt delivers the adult DRI of 150 micrograms (see table 9.3, page 189). This action has proved to be powerfully effective. Suppliers of popular noniodized salts advertise the presence of minerals in their products in general terms, yet the amounts of iodine in micrograms are not disclosed or fall far short of DRIs due to losses during the drying process.86, 93

TABLE 9.3 Iodine in salt and dried sea vegetables

 

 

Dietary Source of Iodine

Nutrient tables lack data on the iodine content of various foods due to the immense variability among crops (or vegetables) from different regions. Amounts in soil vary from one location to another depending on the extent to which flooding, glaciation, or rainfall has leached iodine from the soil, eventually depositing this mineral into the oceans. Some plant foods from the ocean are excellent sources of iodine and other nutrients; in fact, in Japan, where National Seaweed Day (February 6) is celebrated, recommendations for public health advise an increased consumption of sea vegetables.94 The challenge lies in knowing how much iodine you are getting. Raw and dried sea vegetables (including powders and kelp tablets) are generally high in iodine, though amounts of digestible iodine vary as much as eightfold from one batch to another. Much of this mineral is lost to the air during the drying process. Iodine in dried kelp can vary between 0.1 percent and 0.8 percent of the dry weight. Quantities are higher in sea vegetables that grow near coral reefs. It can be difficult to find a supplier with accurate information about iodine content. Kelp tablets may deliver the stated amounts of iodine, though amounts may be underestimated. Some people use a guideline of ¼ teaspoon (1 milliliter) of kelp every four days to meet their iodine DRI. (See table 9.3, page 189.) It is preferable to consume one’s recommended intake of iodine in small but frequent amounts daily or once or twice a week than to consume a large dose less frequently.85, 86, 90–92, 94, 95 Commercially available hijiki seaweed has been found to contain significant amounts of the toxic and carcinogenic element arsenic, and consumers have been advised to avoid it.96 (Also see page 233 in chapter 11.)

Последнее изменение этой страницы: 2016-08-11

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