| ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Calcium is the most abundant mineral in the body, with 99% found in the bones and teeth. In addition to being an integral part of bones, calcium plays roles in muscle contraction, blood clotting, the transmission of nerve impulses, enzyme activation, and the secretion of some hormones. The recommended daily intake of calcium is 1-1.5 g (the amount found in about 3-5 8 oz. glasses of milk) depending on the individual, whereas the average American gets 700-800 mg per day (1). Additionally, the calcium needs of those on high protein diets are increased. Just a few of the benefits of calcium supplements are reduced risk of developing osteoperosis and hypertension, and calcium supplementation may also reduce body fat.
2. What are the benefits of calcium supplementation?
- Reduced body fat - There are two ways in which calcium supplementation
may effectively reduce body fat, but one of them runs some risks. High levels
of dietary calcium (in the absence of vitamin D) suppresses the active form
of vitamin D, 1,25(OH)(2)D(3), which in turn decreases the amount of calcium
in adipocytes (fat cells), which stimulates lipolysis and inhibits lipogenesis
by upregulating UCP2 (2). Accordingly, a 600 mg calcium supplement for one
year increased weight loss in African Americans by 4.9 kg, and mouse studies
have confirmed the effects of increasing dietary calcium on body fat (3).
It should be noted, though, that this method runs some risks, as higher levels
of dietary calcium and the following suppression of 1,25(OH)(2)D(3) has been
correlated with a 32% higher risk of prostate cancer (4), although another
study disputes this finding (5).
The other mechanism for fat loss with calcium is that it reduces the digestibility of fat (6). In many cases this may not be desired, but it may serve to reduce the total number of calories absorbed.
- Buffering capacity - Calcium intake becomes especially important
when one goes on a high protein diet. The body keeps levels of calcium in
the blood very stable, and when calcium is not available it takes calcium
from bone, causing net bone loss over time. Large amounts of protein can
lead to acidosis, increasing the body's buffering requirement, and this can
cause calcium excretion to outweigh intake (9, 10). Adequate amounts of calcium
will prevent this effect, and the recommended amount is a calcium to protein
ratio of 20:1 (mg:g) (10), or 1 gram of calcium for every 50 grams of protein,
and many of us on high protein diets, especially in the form of supplements,
do not receive even close to this amount.
- Reduced risk of osteoperosis and hypertension - Osteoperosis and hypertension are both common ailments seen with aging, and calcium intake has been well established as having a role in both. A recent meta-analysis concluded that calcium supplementation help prevent bone loss and osteoperosis (7), and higher intake of calcium is associated with reduced risk of hypertension (1). In both cases the effect is relatively modest, but other factors may work in conjunction with calcium to reduce overall risk (such as decreased sodium and proper amounts of magnesium).
3. What is the best form of calcium?
There has been some debate over the relative bioavailability of calcium carbonate and calcium citrate. The best source to turn to, in this case, is a recent meta-analysis of 15 studies, which concluded that calcium citrate is 22%-27% more bioavailable (11). Additionally, citrate aids in the inhibition of calcium stones (8). Coral calcium is also more bioavailable than calcium carbonate, and it contains other beneficial minerals as well (12).
4. What are some good supplements to take with calcium?
Vitamin D and calcium play many synergistic (as well as antagonistic) roles with one another, and vitamin D can also increase the bioavailability of calcium, one of reasons for its inclusion in milk products. This also allows for a balance of nutrients and keeps one from suppressing the other. The case of calcium and magnesium is a similar one. Bone mass is not only determined by calcium, but by calcium:magnesium ratio – too much calcium in the absence of magnesium can actually end up reducing bone mass. The recommended ratio for calcium to magnesium generally falls in the 1:1-2:1 area, so a magnesium supplement is warranted if supplementing with large amounts of calcium. Many supplements combine calcium, magnesium, and vitamin D all together for simplicity.
If you have any questions or comments regarding this article, please email dvdtlsn@bulknutrition.com.
No part of this article may be reproduced in any form without the permission of David Tolson or Mike McCandless.
