For these popular pills, the evidence has been mixed. Here's advice about getting the recommended amounts of both nutrients.
In the body, calcium and vitamin D work together to build and maintain healthy bones. Many adults (especially women) take these two nutrients in supplement form, hoping to stave off osteoporosis, the bone-weakening disease that leaves older people prone to fractures. But how do these supplements affect cardiovascular health?
The answer is a bit complicated. Here are the key points, with additional context and advice below:
- Some studies suggest that taking calcium supplements may raise heart disease risk, but others do not.
- Low blood levels of vitamin D have been linked to a higher heart disease risk. But taking vitamin D supplements does not appear to lower that risk.
- Some evidence hints that taking calcium and vitamin D together might slightly increase the risk of stroke. But the largest study to date found no increased stroke risk.
Selected food sources of calcium |
|
|
Recommended Dietary Allowance per day: |
|
|
Food and serving size |
Calcium (mg) |
|
Plain yogurt, 1 cup |
415 |
|
Cheddar cheese, 1 oz |
306 |
|
Milk, nonfat, 1 cup |
302 |
|
Orange juice, fortified, 6 oz |
200-260 |
|
Tofu, firm, made with calcium sulfate, 1/2 cup |
204 |
|
Salmon, pink, canned, with bones, 3 oz |
181 |
|
Spinach, cooked, 1/2 cup |
120 |
|
White beans, 1/2 cup |
80 |
Source: USDA National Nutrient Database for Standard Reference.
Selected food sources of vitamin D |
|
|
Recommended Dietary Allowance per day: |
|
|
Food and serving size |
Vitamin D (IU) |
|
Salmon, pink, cooked, 3 oz |
444 |
|
Tuna fish, canned in oil, drained, 3 oz |
229 |
|
Sardines, canned in oil, drained, 3 oz |
165 |
|
Milk, nonfat, fortified, 1 cup |
116 |
|
Plain yogurt, fortified, 1 cup |
115-127 |
|
Orange juice, fortified, 6 oz |
75 |
|
Egg, whole, cooked, 1 large |
44 |
|
Cheddar cheese, 1 oz |
7 |
Source: USDA National Nutrient Database for Standard Reference.
Calcium connections
Make no mistake — the above findings refer only to supplements, not the food sources of these nutrients. There's no evidence that calcium from food increases cardiovascular risk. "In fact, observational studies suggest that people who consume higher amounts of dietary calcium, such as from yogurt or low-fat dairy products, tend to have lower rates of diabetes and heart disease," says Dr. JoAnn E. Manson, professor of medicine at Harvard Medical School. Calcium is also one of the key minerals involved in blood pressure control.
Studying the health effects of calcium supplements has been complicated, in part because so many people take them. Also, osteoporosis and heart disease have shared risk factors, including a lack of exercise and an unhealthy diet. So people who take calcium to prevent or treat osteoporosis may also be more likely to have heart disease.
In theory, calcium supplements may quickly raise blood calcium levels. This excess calcium might be more likely to be deposited in the heart's arteries, thereby raising the risk of a heart attack. However, evidence from the Women's Health Initiative trial, which Dr. Manson helped lead, doesn't support that idea. After a follow-up of seven years, women who were randomized to take 1,000-milligram (mg) calcium supplements daily (with vitamin D) had similar amounts of calcification in their heart arteries as the women who took placebos.
Vitamin D dilemmas
Starting about 15 years ago, a number of observational studies reported higher rates of heart disease among people with low blood levels of vitamin D. But when researchers put vitamin D to the test in randomized trials, the results were clear: the supplements were no better than a placebo for preventing heart attacks, strokes, or deaths from heart disease. The latest study, published in JAMA Cardiology last year, pooled data from 21 trials involving a total of more than 83,000 people.
What might explain these findings? A low vitamin D level might reflect overall poor health yet not be a cause of the poor health. For one thing, people who are obese tend to have lower vitamin D levels because the vitamin gets stored in fat tissue. Also, because our bodies generate vitamin D from sun exposure, people who rarely spend time outdoors have lower blood levels of the vitamin. Physically active people often exercise or spend time outside, and those healthy habits not only raise vitamin D levels but also directly lower heart disease risk.
Many people can make all the vitamin D they need by going outside midday for about 10 minutes without sunscreen. But the color of your skin (and the area of skin that's uncovered), your geographic location, the time of year, and other factors can alter that estimate quite a bit. The once-common practice of vitamin D testing has fallen out of favor, and the optimal blood level is also somewhat controversial.
Vitamin D plus calcium
Last year, the Harvard Heart Letter briefly mentioned a study that found a slightly higher risk of stroke among people who took calcium and vitamin D supplements together. The study pooled findings from 20 trials, most involving postmenopausal women who took 500 mg to 1,000 mg of calcium and 400 international units (IU) to 1,000 IU of vitamin D daily. However, the largest and longest of these trials was the Women's Health Initiative, and it found no increased risk of heart attack or stroke in women taking both supplements together.
Who needs these supplements?
It's always best to get your nutrients from foods rather than pills. Try to get most of your calcium and vitamin D from your diet (see "Selected food sources of calcium" and "Selected food sources of vitamin D"). If you aren't meeting the Recommended Dietary Allowance from the food you eat, you can fill any gaps with a supplement. This is especially important for postmenopausal women who have low bone density (osteopenia) or osteoporosis, says Dr. Manson. But don't assume that "more is better," as too much of these nutrients might actually be harmful. Take any calcium supplements with food, and limit yourself to 500 mg at a time, as your body can't absorb more than that.
Image: Goodluz/Getty Images
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
Disclaimer:
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
"Vitamin" - Google News
January 17, 2020 at 11:42PM
https://ift.tt/38kYOi7
Calcium and vitamin D supplements: Good, bad, or neutral for cardiovascular health? - Harvard Health
"Vitamin" - Google News
https://ift.tt/34WnbBL
Shoes Man Tutorial
Pos News Update
Meme Update
Korean Entertainment News
Japan News Update
0 Comments:
Post a Comment