David Baxter PhD
Late Founder
Panel urges us not to go overboard on vitamin D and calcium
by Dr. Marla Shapiro, CTV Health News
November 30, 2010
Is vitamin D a runaway train? Some of us would argue that our enthusiasm for vitamin D has been outpaced by the evidence. That is to say that not all the evidence is in when it comes to how much we should be taking. We have seen the recommendations in Canada rise to as high as 2,000 IU a day, and we do know that many Canadians are vitamin D deficient. So where exactly do we stand?
The evidence that we do have for vitamin D and cardiac and cancer reduction is emerging but at present, there is no significant association shown in risk reduction in these domains; the data has been somewhat inconsistent. We do have good data that vitamin D offers protection for colorectal cancer protection but there has been no evidence of protection for other cancers such as gastric, esophageal, kidney, ovarian and pancreatic.
We do know that calcium and vitamin D are two essential nutrients when it comes to bone health. To help clarify the issues, both the American and Canadian governments asked the Institute of Medicine to task a group of experts with reviewing the state of the evidence and science and update what are called nutrient reference values. The bottom line of the report is that most Canadians and Americans are receiving adequate amounts of calcium and vitamin D and there is some emerging data that tells us too much of these nutrients could be harmful.
The science tells is that on average, 500 mg of calcium meets the requirements of children between birth and three years old, and 800 mg from ages 4-8. Adolescents, who are going through bone growth, need more: 1,300 mg per day. Women 19 to 50 and men up to 71 require, on average, 800 mg of calcium a day. Women over 50 and both men and women over 71 should have about 1,000 mg of calcium a day.
When we talk about calcium we do mean from all sources -- both food and diet.
Now what about vitamin D? this is where it gets a bit more complicated. We get our vitamin D from the diet and from sun exposure. The committee found that most adults only require 400 IU of extra vitamin D per day, although those over 71 likely require as much as 800 IU per day.
The committee felt that the cutoff points at what is called "vitamin D deficiency" are set much higher than need be.
The committee did conclude that once intake surpasses 4,000 IU of vitamin D and 2,000 mg of calcium, the risk for harm increases.
The guidelines do challenge the "more is better" statement that some have assumed about vitamins in general. We have seen that often more is not better but can be harmful. It is reassuring to know that lower levels of D supplements are likely adequate and equally reassuring to note that the 2,000 IU recently suggested as the upper range by Osteoporosis Canada is safe.
by Dr. Marla Shapiro, CTV Health News
November 30, 2010
Is vitamin D a runaway train? Some of us would argue that our enthusiasm for vitamin D has been outpaced by the evidence. That is to say that not all the evidence is in when it comes to how much we should be taking. We have seen the recommendations in Canada rise to as high as 2,000 IU a day, and we do know that many Canadians are vitamin D deficient. So where exactly do we stand?
The evidence that we do have for vitamin D and cardiac and cancer reduction is emerging but at present, there is no significant association shown in risk reduction in these domains; the data has been somewhat inconsistent. We do have good data that vitamin D offers protection for colorectal cancer protection but there has been no evidence of protection for other cancers such as gastric, esophageal, kidney, ovarian and pancreatic.
We do know that calcium and vitamin D are two essential nutrients when it comes to bone health. To help clarify the issues, both the American and Canadian governments asked the Institute of Medicine to task a group of experts with reviewing the state of the evidence and science and update what are called nutrient reference values. The bottom line of the report is that most Canadians and Americans are receiving adequate amounts of calcium and vitamin D and there is some emerging data that tells us too much of these nutrients could be harmful.
The science tells is that on average, 500 mg of calcium meets the requirements of children between birth and three years old, and 800 mg from ages 4-8. Adolescents, who are going through bone growth, need more: 1,300 mg per day. Women 19 to 50 and men up to 71 require, on average, 800 mg of calcium a day. Women over 50 and both men and women over 71 should have about 1,000 mg of calcium a day.
When we talk about calcium we do mean from all sources -- both food and diet.
Now what about vitamin D? this is where it gets a bit more complicated. We get our vitamin D from the diet and from sun exposure. The committee found that most adults only require 400 IU of extra vitamin D per day, although those over 71 likely require as much as 800 IU per day.
The committee felt that the cutoff points at what is called "vitamin D deficiency" are set much higher than need be.
The committee did conclude that once intake surpasses 4,000 IU of vitamin D and 2,000 mg of calcium, the risk for harm increases.
The guidelines do challenge the "more is better" statement that some have assumed about vitamins in general. We have seen that often more is not better but can be harmful. It is reassuring to know that lower levels of D supplements are likely adequate and equally reassuring to note that the 2,000 IU recently suggested as the upper range by Osteoporosis Canada is safe.
