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minerals

Minerals

Iron

Iron is needed to transport oxygen from the lungs to the cells. It’s also needed for proper immune system functioning and for brain processes.

The required amount is 8 mg of iron for men and post-menopausal women, and 18 mg for pre-menopausal women.

Some foods rich in iron are the following:

  • Legumes, such as beans, lentils and peas (soaking them before cooking improves iron absorbability)
  • Nuts, especially cashews
  • Whole grains, especially brown rice and wheat bran
  • Vegetables, especially spinach and pumpkin
  • Other good sources of iron are: amaranth, dried apricots, tahini, pumpkin seeds, and dark chocolate1

Important facts:

The absorption of iron is improved when iron-rich foods are consumed together with foods containing vitamin C, such as citrus fruits, green leafy vegetables, peppers and cauliflower. Cooking destroys some of the vitamin C in foods, so it’s helpful to consume a mix of raw and cooked foods high in this vitamin. We must also keep in mind that the caffeine in coffee and tea hinders iron absorption, which means that consuming these beverages after eating foods with iron in them will reduce the amount of iron we can absorb. Vegans tend to consume more foods in high in vitamin C, but they still need to be aware of the absorption-reducing effects of consuming coffee and tea.

 

Calcium

Calcium is one of the most important minerals for the growth, maintenance and reproduction of the human body and also helps build and maintain healthy teeth and bones. Maintaining proper levels of calcium throughout life can help prevent osteoporosis. It also aids in blood clotting, transmitting nerve signals, muscular contraction and relaxation, and the release of certain hormones as well as being necessary for normal cardiac rhythms.

It is estimated that it is necessary to consume at least 525 mg daily of calcium in order to prevent problems with the bones, but recommendations vary widely in western populations. The United Kingdom recommends 700 mg daily for adults, while the U.S. considers 1,000 mg for adults, 500 mg daily for 1-3 year olds and 800 mg for 4-8 year olds.2

To obtain this quantity of calcium it is not necessary at all to eat dairy products, since there are many calcium-rich plant foods. Some of the best sources are green leafy vegetables such as kale, collard greens, turnip and mustard greens, and broccoli. Other good sources are legumes, sesame seeds, tahini and dried fruit. In order to maintain optimal levels of calcium, it is recommended that vegans also consume some foods that are fortified with calcium, such as most brands of soy, rice and coconut milk.

 

Zinc

Zinc is needed for proper immune system functioning. It also plays a role in the division and growth of cells, in the healing of wounds, and it’s important for the overall growth of the body.3

The standard recommended daily amount of zinc is 8 mg for women and 11 mg for men. However, vegetable sources of zinc are less well absorbed by the body than animal sources. For this reason, the recommendation for vegans is 12 mg for women and 16.5 mg for men. This is not a serious concern for vegans, since there is no evidence that vegans suffer from zinc deficiency, and there are some studies that show that vegans with lower than recommended levels of zinc do not suffer any ill effects.

Some foods that are rich in zinc are lentils, peanuts, soy, whole pumpkin seeds, sunflower seeds, wheat germ oil, wild rice, azuki beans, hard tofu, chocolate and black tahini. Other foods with lower amounts of zinc are wheat, corn, or almonds.

Important facts:

Some preparation techniques, such as soaking beans, grains and seeds, can reduce the binding of the zinc phytate, and this increases the bioavailability of the zinc.4

 

Iodine

Iodine is needed for proper cell metabolism and for normal functioning of the thyroid gland.

Iodine found in plant foods is variable and depends on the iodine content of the soil in which the plants are grown. There are some well-known health issues, such as goiter, caused by iodine deficiency that have been found in certain places where the traditional diets were lacking in iodine-rich foods and fortified salt or other foods were not available.

An easy way to avoid iodine deficiency is to consume iodized salt. The recommended daily amount for adults is 150 mg, which is easily covered by a half-teaspoon of iodized salt daily, or twice that amount for pregnant women. This is based on salt with 60 mg of potassium iodide added per kilogram (convert), so double check the label on your salt.

For those who do not consume salt, it is also possible to get iodine from a supplement. To cover the needs of the average person, 75 to 150 mcg of iodine should be taken three or four times a week.5

Important facts:

Excessive consumption of iodine over a long period of time may lead to health problems, so it is not recommended that large quantities of seaweed be consumed.

 

Potassium

It is recommended that at least 4,700 mg of potassium be consumed daily. On average, vegans consume more potassium than people who eat animal products.6

The best food sources of potassium are spinach and other green leafy vegetables, tomato juice, tomato sauce, orange juice, bananas, kombu seaweed, legumes and potatoes.


Further readings:

Appelby, P.; Roddam, A.; Allen, N. & Key, T. (2007) “Comparative fracture risk in vegetarians and non-vegetarians in EPIC-Oxford”, European Journal of Clinical Nutrition, 61, pp. 1400-1406 [accessed on 20 November 2016].


1 Cook, J. D.; Dassenko, S. A. & Lynch, S. R. (1991) “Assessment of the role of non-heme-iron availability in iron balance”, The American Journal of Clinical Nutrition, 54, pp. 717-722. Centers for Disease Control and Prevention (1998) “Recommendations to prevent and control iron deficiency in the United States”, Morbidity Mortality Weekly Report, 47, pp. 1-29. Centers for Disease Control and Prevention (2002) “Iron deficiency-United States, 1999-2000”, Morbidity Mortality Weekly Report, 51, pp. 897-899. Mangels, R.; Messina, V.; Messina, M. (2010) The dietitians’s guide to vegetarian diets, 3rd ed., Sudbury: Jones and Bartlett, pp. 530-535. Norris, J. & Messina, V. (2011) Vegan for life, op. cit., pp. 62-67.

2 Eaton, S. B.; Neslon, D. A. (1991) “Calcium in evolutionary perspective”, The American Journal of Clinical Nutrition, 54, pp. S281-S287. Weaver, C. M.; Plawecki, K. L. (1995) “Dietary calcium: Adequacy of a vegetarian diet”, The American Journal of Clinical Nutrition, 59, pp. S1238-S1241. Feskanich, D.; Willet, W. C.; Stampfer, M. J. & Colditz, G. A. (1997) “Milk, dietary calcium, and bone fractures in women: A 12-year prospective study”. American Jounal of Public Health, 87, pp. 992-997. Appelby, P.; Roddam, A.; Allen, N. & Key, T. (2007) “Comparative fracture risk in vegetarians and non-vegetarians in EPIC-Oxford”, op. cit. Bischoff-Ferrari, H. A.; Dawson-Hughes, B.; Baron, J. A.; Burckhardt, P.; Li, R.; Spiegelman, D.; Specker, B.; Orav, J. E.; Wong, J. B.; Staehelin, H. B.; O’Reilly, E.; Kiel, D. P. & Willett, W. C. (2007) “Calcium intake and hip fracture risk in men and women: A meta-analysis of prospective cohort studies and randomized controlled trials”, The American Journal of Clinical Nutrition, 86, pp. 1780-1790 [accessed on 17 November 2016]. Mangels, R.; Messina, V.; Messina, M. (2010) The dietitians’s guide to vegetarian diets, op. cit., p. 356. Norris, J. & Messina, V. (2011) Vegan for life, op. cit., pp. 42-44.

3 Gropper, S. S. & Smith, J. L. (2013) Advanced nutrition and human metabolism, 6th ed., Belmont: Wadsworth.

4 Norris, J. & Messina, V. (2011) Vegan for life, op. cit., pp. 68-69.

5 Ibid., pp. 70-72.

6 Ibid., p. 76.

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