Calcium and vitamin D work together to contribute to good bone health. Calcium is crucial for bone strength; vitamin D is required for bone tissue to absorb calcium, ensuring that bones remain calcium-rich and dense.
It is especially important for people to get enough calcium and vitamin D from childhood through their 20s because most of a person's bone mass is achieved by early adulthood. After that time, bone mass gradually declines throughout the rest of a person's life, and for women, this decline accelerates during the menopause transition. The analogy would be putting enough money in the bank on a regular basis now so that you never become overdrawn or bounce a check. The greatest health risk associated with lack of calcium and vitamin D is osteoporosis, so it's important to get enough of both nutrients now to ensure that you don't end up with broken bones when you're 60.
Calcium and vitamin D play other important roles too. Calcium is essential for proper blood clotting, muscle contraction and nervous system response, and ongoing research into the benefits of vitamin D suggests that it may play a role in cancer prevention, heart disease prevention and diabetes management.
The best way to stock up on calcium and vitamin D is through nutrient-rich foods. You can get higher concentrations of calcium from foods such as dairy products, green leafy vegetables, salmon, tofu, almonds, beans, calcium-fortified orange juice and soymilk. Compared to calcium, vitamin D is more difficult to find in the common foods in a typical American diet. It is present in cod liver oil and some types of saltwater fish and shellfish (salmon, halibut, herring, tuna, oysters, and shrimp), fortified milk and some cereals. Your body also makes vitamin D after exposure to the sun.
Supplements are an easy way to help fortify your diet with calcium and vitamin D. Despite all the research supporting the benefits of these nutrients, the average American woman consumes less than 500 mg of calcium per day in her diet--half the currently recommended daily value. Women ages 11 to 24 require 1200 mg of calcium, while women ages 25 to 50 require 1000 mg of elemental calcium daily. For best absorption, it's best to consume 500 mg of calcium or less at one time. So if your goal is to take 1000 mg of calcium supplements per day, you can do so most effectively by taking one 500 mg supplement in the morning and another in the evening. For vitamin D, the current recommended daily value is 400 International Units (IU), though new research suggests that our needs may be higher (more like 800 to 1,000 IU daily).
Calcium supplements come in the form of calcium carbonate and calcium citrate, and both are similarly well absorbed (however, individuals with reduced levels of stomach acid-i.e., those on acid blocker medications-can absorb calcium citrate more easily). The body most efficiently absorbs calcium carbonate when you take it with food, whereas the body can absorb calcium citrate equally effectively with or without food.
A word of caution, though. A new study published in July 2010 revealed that there are possible cardiac risks related to taking calcium supplements, such as increased chances of heart attack. These risks were not found to be associated with getting calcium through food in your diet. We still need more time to analyze the data from this study, and one can't make decisions based on a single study. With that said, it's best to always talk to your personal physician who can weigh the pros and cons of calcium supplementation with you. It's always best to try to get nutrition through food and not supplements, and if the findings in this study are confirmed, you'll have yet another reason to pick foods high in calcium and leave the supplements behind.
Calcium Study Source:
BMJ-British Medical Journal (2010, July 30). Calcium supplements linked to increased risk of heart attack, study finds. ScienceDaily. Retrieved from http://www.sciencedaily.com/releases/2010/07/100729191154.htm
I have written a couple of articles on calcium recently:
It's important to get your vitamin D levels checked (the 25-OH test). The goal is for the level to be above 30 for optimal bone density, although some doctors say it needs to be above 50 for optimal immune function and prevention of autoimmune disease.
If you're not living near the equator, you're probably low. I often start patients on 2,000 IU daily in the winter (I think the RDA of 400 is pretty wimpy, to be frank), taken with meals (since it's a fat soluble vitamin). There are some great D mulsion products out there that are anywhere from 1,000 to 10,000 IU per drop.
If you do opt for supplementation, make sure you're buying D3 and NOT D2. I find it's hard to budge the vitamin D levels in the Northern climes without a supplement. But if you're absolutely set on skipping D3 supplementation, eating chicken liver twice a week and taking cod liver oil daily may help.
As for calcium, supplementation isn't all it's cracked out to be. For women with osteopenia or osteoporosis, I typically choose a combination product that has a little calcium blended with vitamin D, vitamin K, strontium, magnesium, and boron. Go easy on the calcium supplements.
Also note that the whole campaign of milk being rich is calcium is a big fat marketing hoax. The calcium in dairy products is poorly absorbed. Plus the consumption of milk and dairy products has actually been linked with osteoporosis. Meat and dairy are acidifying, and the body pulls calcium from the bones to neutralize the acid. Yeep! Better stick with dark, leafy, greens, which are rich in minerals like calcium. For optimal absorption, add a tiny splash of vinegar when cooking them.