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Due to numerous inquiries about the use of coral calcium from Okinawa Japan to treat cancer, heart disease, hypertension and a multitude of other health problems we have issued a position statement that will set forth the evidence regarding the purported miraculous therapeutic benefits of Okinawa coral calcium.

The Evidence About Okinawa Coral Calcium Supplements:

Calcium: The Good News

Evidence from recent studies using calcium supplements (not necessarily calcium from coral) have indicated that calcium may be good for the heart, may help to lower blood pressure in about one-third of people with hypertension and may improve blood lipid levels. These calcium research studies have been reported in scientific journals and widely quoted in newspapers such as the New York Times. Unfortunately, many of these studies have been quoted of out context by individuals touting the supposed miraculous benefits of coral calcium. Outrageous claims such as "90 % of all cancers are the result of calcium deficiency" (as was recently claimed in one popular television infomercial) are simply not supported by the scientific evidence. Nor is all the evidence about calcium good.

Calcium: The Bad News

Research from recent calcium studies has shown that too much calcium may not be helpful for preventing fractures associated with osteoporosis and may in fact be linked to increased odds of developing prostate cancer in men.

The research from seven long-term prospective studies done in Europe and the US has not shown any important reduction in risk of fractures with increasing calcium intake. Nine separate studies provide research that shows the strongest and most consistent nutritional factor linked with prostate cancer was high consumption of milk or dairy products. This is hypothesized to be due to high calcium levels inhibiting vitamin D absorption. Higher vitamin D intake has been linked to lower risk for prostate cancer. These observations have yet to be tested in rigorous research trials. For a good summary see The Harvard Health Letter, which recently warned: "If you're looking for consistency in health advice, don't pay too much attention to the studies of calcium intake and cancer."

Okinawa's Drinking Water and Longevity: The Evidence

Most of the health claims being made about coral calcium from Okinawa are based on the fact that the Okinawans are among the world's longest lived people and supposedly drink water containing coral calcium. Although Okinawa may have the world's highest concentration of centenarians, as well as extremely low mortality rates from diseases common in the West such as coronary heart disease, breast and prostate cancers, research shows that it has very little to do with their drinking water, as we explain in detail in our book "The Okinawa Program". Although drinking hard water (high mineral content that includes calcium, magnesium and other minerals) gives the Okinawans a boost in their calcium intakes, they still fall far below the calcium intakes of most Western countries.

Calcium Intake in Okinawa is Lower than in the US: The Evidence

The fact is that when it comes to calcium in the diet, research shows that the United States is actually near the top of the list at about 800 mg per day (USDA 1996) with the Scandinavian countries, such as Finland (1300+mg day) being the world's leaders in calcium consumption. Okinawans actually consume less calcium than their Western counterparts. The average calcium intake in Okinawa is only about 500 mg a day (1998 Okinawa Prefecture Health and Nutrition Survey). This is a far cry from claims of "100,000 mg of calcium a day" for the average Okinawan as claimed in a recent TV infomercial.

Why the Okinawans Live Long: The Evidence

The real reasons for the health and longevity phenomenon in Okinawa are multiple but include the following:

  • Eating a low-calorie, mostly plant-based diet with plenty of fish and soy foods and a great variety of vegetables as well as moderate amounts of the right kinds of fats
  • Getting regular, life-long physical activity
  • Enjoying strong social and community support for the elderly
  • Realizing the health benefits of a universal, affordable medical-welfare system that focuses on a preventive approach and integrates much of what is good about Eastern medicine with the best of the West.

We do not endorse coral calcium supplements from Okinawa for the following reasons:

  • Coral calcium supplements have not been proven to be any more effective than regular calcium supplements -- though they are far more costly.
  • We are not aware of any scientific studies that support any of the more dramatic health claims made for coral calcium supplements.
  • The claim that you can enhance health by making the body more alkaline has no basis in science.

The Okinawan Reef Crisis

And lastly, Okinawa's reefs are facing an unprecedented crisis due to sedimentation from large scale development, global warming and pollution. Over half have been lost in the last five years. We, at The Okinawa Centenarian Study, take the position that the reefs of Okinawa need to be protected rather than exploited.

Blast fishing destroys Okinawa's coral reefsThe world's coral reefs are the rainforests of the sea, an incredible biodiversity reservoir. They provide food for 100 million coastal peoples, are a major attraction for millions of tourists, protect coastlines and are a source of new medicines. Sadly, all over the world reefs are facing an unprecedented crisis due to over-fishing, blast and poison fishing, sedimentation, global warming and pollution. According to recent research by Reef Check, over 16% of the world's coral reefs have been lost in the last five years alone, with another 27% severely threatened. We support organizations such as Reef Check that promote conservation of the world's remaining coral reef ecosystems. For more information see

Further Evidence

Coral Calcium research and information on coral calcium supplementation from other health experts *:

  • Spotlight on Coral Calcium
    Prevention magazine's registered dietician Tamara Schryver's advice helps you evaluate Coral Calcium supplement ads. Featuring comments from Dr. Robert Heaney, MD, Professor of Medicine with the Osteoporosis Research Center at Creighton University
  • Counting on Coral Calcium?
    Alternative health and integrative medicine expert Dr. Andrew Weil's opinion on coral calcium supplementation.
  • "Coral Calcium Scams - Special Report", a consumer health watchdog, offers a wealth of information about coral calcium claims made in books and television shows by sellers of popular coral calcium supplements and coral calcium products.
  • The Berkeley Wellness Guide on coral calcium
    UC Berkeley Wellness Letter debunks the wild claims made for coral calcium supplements, stating: "There is no evidence that coral calcium cures or treats any disease, or that it is better than a basic, inexpensive calcium carbonate pill."
  • Quackwatch Expose on Coral Calcium
    Dr. Stephen Barrett, M.D. offers detailed information on coral calcium and Robert Barefoot -- one of the most popular sellers of coral calcium supplements and coral calcium products

More Information on Coral Calcium and Calcium Supplements *:

  • Calcium Information Sheet
    The Vegetarian Society of the United Kingdom provides information about calcium, including calcium rich foods, calcium sources, calcium absorption and recommended daily amounts of calcium
  • Calcium Supplements and the prevention of Osteoporosis
    Useful information on calcium supplements from The National Osteoporosis Foundation, such as the following: "A high calcium intake will not protect a person against bone loss caused by estrogen deficiency, physical inactivity, smoking, alcohol abuse or various medical disorders or treatments."
  • Berkeley Wellness Guide to Supplements
    A good review of information on calcium supplements.
* The Okinawa Centenarian Study team is not responsible for the content found in pages linked to from this site.