Even though osteoporosis is a largely preventable disease through diet and exercise, osteoporosis and its complications are now considered by the World Health Organization to be the second-leading health care problem, behind only cardiovascular disease. Osteoporosis is a condition that breaks down the skeleton, making bones more fragile and more likely to spontaneously fracture, especially in the spine and hip. Bone loss can result from a variety of reasons including insufficient dietary intake of essential nutrients, pollutants, toxins, smoking, menopause, lack of physical activity and heredity.
Attempting to retard bone loss through clinical nutrition, calcium supplementation and food fortification has been shown in well-controlled clinical trials to be very effective. Indeed, calcium has been the leading dietary supplement in bone nutrition for decades. However, scientific advancements in our understanding of bone physiology, structure and nutrient interaction has resulted in the discovery of a number of other nutrients that may play as big a role as calcium in maintaining a healthy skeletal system well into old age.
The Calcium Dilemma
Among the greatest changes in the thinking of the nutritional community over the past decade has been the re-evaluation of the importance and place of calcium in our diet and supplements. Recent studies have started to analyze the differences in the metabolism of calcium under different circumstances within the body such as menopause, a time during which calcium is not well absorbed. These studies have led to a different view of dietary and supplemental recommendations for calcium.
The cost-effectiveness of calcium supplementation depends not only on the cost of the supplement but on how well it is absorbed. It doesn’t matter how cheap a supplement is if most of it ends up in your toilet as opposed to your blood stream. This also applies to milk and other milk derivatives such as yogurt and cheese. Recent findings from human studies have demonstrated that milk calcium (tri-calcium phosphate) is no better absorbed than many other forms of synthetic calcium used in dietary supplements, including calcium carbonate, gluconolactate, citomalate, chloride, lactate, acetate and citrate. These studies have found that the most readily absorbable form of calcium is bis-glycinocalcium taken on an empty stomach, followed by calcium citromalate taken with a meal.
The Phosphorous Problem
Eighty-five percent of all phosphorous found in the human body is in the skeleton. Although it is an essential nutrient, there is concern that excessive amounts may be detrimental to your bones. Dietary phosphorous intake has risen over the past 20 years because of its increased use in food additives and cola beverages. In the U.S., phosphorous intake is between 1,000–1,500mg/day, well above the currently recommended level for adults of 700mg/day. However, a series of studies from Creighton University in Nebraska has found that it is actually the ratio of calcium to phosphorus intake that is important. These studies found that if calcium intake increases without a corresponding increase in phosphorous, the risk of phosphorous insufficiency rises and vice versa. These studies found that your calcium:phosphorous ratios should not be higher than 1:2. Therefore, patients with osteoporosis should have phosphorous in some of their calcium supplements.
The Magnesium Mystery
Two-thirds of all magnesium in the human body is located in the skeleton. Without an adequate dietary intake of magnesium, calcium metabolism is negatively impacted. Too little magnesium in your diet can lead to the breakdown of bone. One study showed that an intake of 300-400 mg/day of magnesium in post-menopausal women resulted in a significant increase in bone density after one year.
The Fluoride Question
The issue of dietary fortification, supplementation or artificially fluoridated water is a contentious one. There is a serious question as to whether sodium fluoride supplementation actually benefits bone health. There is some data that suggests that fluoride is a stimulator of bone formation. However, a large study by the Mayo Clinic showed that fluoride treatment didn’t impact the incidence of fracture rates. Therefore, the issue of fluoride supplementation to help bone health still remains a question.
The Zinc Factor
Zinc is an important factor in the mineralization of bone. During periods of zinc deficiency, bone density is greatly reduced, and excessive excretion of zinc is related to osteoporosis. The times for possible supplementation with zinc are during adolescence or for those involved in excessive exercise, during a period of dietary restriction, or following periods of prolonged illness where zinc levels may be under stress due to increased rates of growth and/or bone turnover. The current recommended daily allowance for zinc is 12mg/day, but research suggests optimal bone health is better achieved at a level of 30mg/day.
The Vitamin D Dynamic
Vitamin D helps to keep blood calcium and phosphorous concentrations within the normal range to maintain essential cellular functions and to promote mineralization of bone. As such, D3 deficiency has been shown to play an important role in osteoporosis. Vitamin D3 is synthesized in the skin through exposure to sunlight. Vitamin D3’s biologically active form is 1-alpha, 25-dihydroxy vitamin D, and it is possible for vitamin D3 levels to be low but the active form to be within normal limits. Because of recent advances in gene technology and the identification of the vitamin D receptor gene (VDR) that may indicate greater susceptibility to osteoporotic disease, vitamin D is back under scientific scrutiny.
Studies of supplementary vitamin D for prevention of osteoporotic fractures concluded that the effectiveness of vitamin D alone is uncertain, but it does work well in conjunction with calcium. There is some discrepancy in how much vitamin D should be taken. Traditionally levels between 400-600IU/day are recommended. A note of caution: excessive intake of vitamin D can result in low blood calcium and calcification of arterial walls and the kidney. However, the dose of vitamin D that causes significant hypocalcaemia is highly variable between individuals but is rarely less than 1,000mcg/day.
The K Vitamins (K1 and K2)
The K vitamins are a group of napthoquinones that seem to retard bone loss in elderly populations. Vitamin K1 (phylloquinone) and vitamin K2 (menaquinone) differ regarding food sources (green vegetables and fermented products, respectively), bioavailability and intermediate metabolism. Studies suggest that K2 may have a greater effect in maintaining bone density than K1. However, the majority of dietary intake of K1 is lost by excretion so we need a continuous dietary supply of both forms to maintain appropriate levels in our body.
The Matter of Soy
Ipriflavone is a synthetic form of naturally occurring isoflavones found in soy. Ipriflavone shows promise for its ability to prevent deterioration of bone density. It also appears to have a positive effect on patients who have undergone ovariectomy and steroid use.
Although calcium is still the most important nutrient for bone health, if you have osteoporosis or are predisposed to it, supplementation with these other nutrients is worth trying to help build and maintain bone density.