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Vitamins and supplements

If you’re eating lean protein and lots of fresh fruits and vegetables, you should be getting more than enough vitamins, minerals, and other nutrients from your healthy diet. Unfortunately, most people are not eating five or more servings of fruits and vegetables per day. So should you take multivitamins, antioxidants, and other supplements?

Multivitamins
According to the U.S. Preventive Services Task Force, there is insufficient evidence to recommend the use of vitamins to prevent heart disease and cancer1. Prostate cancer may be the exception—vitamin E and selenium seem to have protective effects. There are some diseases where vitamins are highly recommended. For example, folic acid reduces the risk of neural tube defects in pregnancy, and vitamin D and calcium reduce the risk of fractures in elderly women with osteoporosis.

What do doctors do? In a study from Emory University, researchers found that two-thirds of female physicians have taken vitamin and mineral supplements, and almost half do so regularly2. The most common supplements are folic acid, vitamin E, vitamin C, and calcium.

There are almost no health risks to taking a daily multivitamin3. Also, an annual supply of multivitamins is inexpensive if you buy a generic brand in bulk. The brand name doesn’t matter because most multivitamins provide at least 100 percent of the daily recommended dose4. Do what doctors do. Take a daily multivitamin as part of your healthy diet.

Vitamin D
Vitamin D is important for bone health. It regulates the amount of calcium in your blood and helps maintain a strong skeleton. In a study from Harvard Medical School, postmenopausal women who consumed more than 12.5 micrograms (500 IU) of vitamin D per day had a 37 percent lower risk of hip fracture5. Another Harvard study found that vitamin D reduced the risk of falls in the elderly by 22 percent6. In addition to bone health, there is evidence that vitamin D prevents hypertension and cancer.
 
In young people, vitamin D deficiency causes rickets. Symptoms include bone pain, fractures, and bow legs. Before the 1930s, rickets was a major public health problem in the United States until the government required that milk be fortified with vitamin D. Our Paleolithic ancestors didn’t have vitamin-fortified milk. So why didn’t they get rickets? Your skin naturally makes vitamin D when it’s exposed to ultraviolet light from the sun. Fifteen minutes of sunshine twice a week is all it takes to make the recommended amount. Other sources of vitamin D include fish such as salmon, mackerel, and tuna.

Although vitamin D is readily available from sunlight, researchers have found that 36 percent of young people and 57 percent of hospital patients are deficient in vitamin D7. Kids would rather play video games than play outside. It’s not just kids. Many workers are stuck in their cubicles all day. The sun has gone down by the time they’re finished work. Don’t miss out on your vitamin D. Get some sun, eat some fish, and take a multivitamin.

Osteoporosis
Osteoporosis is a disease of weak bones. In the United States, it affects about 2 million men and 8 million women8. Another 34 million Americans have osteopenia, or low bone mass, which can lead to osteoporosis. Osteoporosis and osteopenia increase the risk of fractures, especially in the hip, spine, and forearm. The average 50-year-old woman has a lifetime fracture risk of 18 percent in her hip, 16 percent in her spine, and 16 percent in her forearm. Fractures are more than just an inconvenience. In older patients, there is a 15–20 percent chance of dying from the complications of a hip fracture in the first year.

How do you prevent osteoporosis? The answer is lots of vitamin D and exercise, especially when you’re young9. Bone is living tissue and responds to exercise by becoming stronger and denser. Vitamin D helps your bones absorb calcium, and build new bone. Most of your bone mass is developed in adolescence and young adulthood, with nearly 90 percent accumulated by age 1810. Your body continues laying down bone until about the age of 30. After that, you usually lose a small amount of bone mass every year. You can slow down or even stop this age-related bone loss with vitamin D and exercise.
 
In the Harvard Nurses’ Health Study, researchers found that the risk of hip fracture was 41 percent lower in postmenopausal women who walked more than 4 hours a week, compared to those who walked less than 1 hour11. Walking is good, but vigorous exercise is even better. Researchers from the University of Helsinki found that older men had a 62 percent lower risk of hip fracture if they jogged regularly12.
 
Milk and Calcium
Wait a minute. Doesn’t milk build strong bones? Forget the TV commercials and magazine ads. Scientists have found that drinking milk and eating dairy foods are almost useless for preventing osteoporosis. Milk contains a lot of protein in addition to calcium. When protein is digested in your body, calcium is leached from your bones to buffer the acid that is produced13. This means that the gain in calcium from milk is offset by the loss of calcium from your bones. The overall effect is roughly neutral, and that’s why milk doesn’t do much to prevent osteoporosis.

In an 18-year study of over 70,000 postmenopausal women, Harvard researchers found that drinking milk or eating a high-calcium diet had no effect on reducing the risk of hip fracture14. Similarly, researchers at the University of Alabama reviewed 46 studies on dairy foods and bone health, and found only a small benefit in women under the age of 3015. There was no improvement in anyone else. The researchers concluded, “The body of scientific evidence appears inadequate to support a recommendation for daily intake of dairy foods to promote bone health in the general U.S. population.”

Our Paleolithic ancestors ate a lot of protein. So why didn’t the calcium leach from their bones and cause osteoporosis? Fruits and vegetables are usually alkaline in pH, and they naturally buffer the acid from protein digestion16. Also, Paleolithic people built strong bones by exercising regularly, and getting lots of vitamin D from sunlight and fish.

Dairy foods were only introduced into the human diet about 6,000 years ago. For most of human history, there was no milk, cheese, or yogurt. Don’t be brainwashed by the milk marketers. You don’t need milk to build strong bones.

References
  1. U.S. Preventive Services Task Force. (2003). Routine vitamin supplementation to prevent cancer and cardiovascular disease: Recommendations and rationale. Ann Intern Med. 139(1):51–55.
  2. Frank E, Bendich A, and Denniston M. (2000). Use of vitamin-mineral supplements by female physicians in the United States. Am J Clin Nutr. 72:969–75.
  3. Fletcher RH, and Fairfield KM. (2002). Vitamins for chronic disease prevention in adults. JAMA. 287:3127–3129.
  4. Willett WC and Stampfer MJ. (2001) What vitamins should I be taking, doctor? N Engl J Med. 345(25):1819–1824.
  5. Feskanich D, Willett WC, and Colditz GA. (2003). Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women. Am J Clin Nutr. 77:504–11.
  6. Bischoff-Ferrari HA et al. (2004). Effect of vitamin D on falls. JAMA. 291(16):1999–2006.
  7. Holick MF. (2006). High prevalence of vitamin D inadequacy and implications for health. Mayo Clin Proc. 81(3):353–373.
  8. Kelley GA, Kelley KS, and Tran ZV. (2001). Resistance training and bone mineral density in women: a meta-analysis of controlled trials. Am J Phys Med Rehabil. 80:65–77.
  9. Kohrt WM et al. (2004). Physical activity and bone health. Med Sci Sports Exerc. 36(11):1985–1996.
  10. Kass-Wolff JH. (2004). Calcium in women: healthy bones and much more. JOGNN. 33:21–33.
  11. Feskanich D, Willet W, and Colditz G. (2002). Walking and leisure-time activity and risk of hip fracture in postmenopausal women. JAMA. 288(18):2300–2306.
  12. Kujala UM et al. (2000). Physical activity and osteoporotic hip fracture risk in men. Arch Intern Med. 160(5):705–708.
  13. Weaver CM, Proulx WR, and Heaney R. (1999). Choices for achieving adequate dietary calcium with a vegetarian diet. Am J Clin Nutr. 70(suppl):543S–8S.
  14. Feskanich D, Willett WC, and Colditz GA. (2003). Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women. Am J Clin Nutr. 77:504–11.
  15. Weinsier RL, and Krumdieck CL. (2000). Dairy foods and bone health: examination of the evidence. Am J Clin Nutr. 72:681–9.
  16. Tucker KL et al. (1999). Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. Am J Clin Nutr. 69:727–36.

Copyright © 2009 by Paul Lem, M.D.
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