Calcium and Vitamin D: How Much is Enough?

We’ve all seen people who seem to have horrible osteoporosis — their backs are bent forward, their necks stooped. All of us want to prevent that -- but how? More milk? More calcium? More vitamin D? Supplements?

Recent research has brought up questions about our calcium intake and how much we really need. However, the question is more nuanced than that. We have to consider vitamin D separately, as it has different research and recommendations and studies over the past few years have shown that many of us are deficient.
Regarding calcium, studies have shown that people with the very lowest intakes do appear to have a higher fracture risk. However, finding a connection between higher calcium intake and stronger bones has so far been hard to prove. Most studies depend on people remembering how much calcium they had as a child (30-40 years prior) and then studying their bone density now – and these studies have shown no benefit to drinking extra milk as a child. In addition, one study showed that drinking higher amounts of milk as an adult may actually be associated with an increased risk of fractures. Note—the studies are not saying that the milk led to the fractures, just that people who drank more milk as adults were also more likely to have fractures. It’s worth noting that for adults, the extra milk consumption has just not been shown to be beneficial at this time. What's more, taking calcium supplements as an adult has been associated with small possible increases in coronary disease (but possibly only if you take them with food) and kidney stone risk.
What about vitamin D supplements? Research has shown that many of us are deficient (due to diet, less sun exposure and a variety of other factors). While some researchers see the benefit of vitamin D supplementation, especially for certain age and deficiency groups, there’s no across-the-board agreement.
Where does that leave us? How much you need depends on your age group and health status. However, there are a couple of facts that are true for everyone:
  • Calcium from your diet and calcium from supplements is not the same thing. Your body does not use them in the same way. Notably, dietary calcium reduces your risk of kidney stones, while supplemental calcium increases it. Getting as much of your calcium and vitamin D needs met from your diet is ideal, with supplementation only when necessary. When looking for calcium rich foods , try to get the majority from either leafy greens, calcium fortified grains, tofu, or low-fat/non-fat dairy.
  • Certain lifestyle habits are important for bone health. Exercise has been proven to improve bone mass, while excessive carbonated beverages, smoking and alcohol all lower bone mass.
That's a lot to take in, right? So where does that leave us? Here are my recommendations on how much calcium and vitamin D you need at each age for your bones and your overall health.
Age 10 to 30 in good health:
The second and third decades of life (from age 10-30) are the times of peak bone building. Once you hit 30, the amount of bone you have is your maximum—it will only decrease from there. That’s why adequate calcium and vitamin D in this age group is crucial. Most dietary guidelines say this group is age 9 to 18, but since your bones are still building in your 20s, I put you here.
Calcium: Unfortunately, kids and young adults in this group take in lower than recommended doses, with an average intake of 100mg/day. Aim for 1300-1500 mg/day of calcium and 600 IU of Vitamin D. In addition:
  • Maximize how much you can get in your diet; most children will need a supplement to have sufficient calcium (not sure? Check with your pediatrician).
  • Don’t forget the impact of exercise! In one study of people age 13 to 27, regular weight-bearing exercise and maintaining a normal body weight were the most important factors for maximizing bone mass.
  • Avoid excessive caffeine and carbonated beverages as they may contribute to poorer bone mass.
Vitamin D: The Institute of Medicine and American Academy of Pediatrics recommend intake of 600 IU/day. Most children and adolescents won’t get enough vitamin D through diet alone, so supplementation plays an important role.
Adults over age 30 without osteoporosis
This is the tougher area. There is no evidence that calcium supplementation is beneficial in a healthy adult who does not have osteoporosis or osteopenia. In addition, the risks of heart disease and kidney stones may outweigh the benefits. As a result, the U.S. Preventive Task Force does not recommend taking calcium supplements if you’re in this age group.
Calcium: Aim to get 1000mg/day (1200mg/day if you’re over 70) in your diet. Any benefit of further supplementation is outweighed by the associated risks.
Vitamin D: Adults at risk for low vitamin D should either take a supplement or have their vitamin D levels checked. Risks for low vitamin D include inadequate sun exposure (that would include most of us in the winter, especially if you live in the northern part of the country), the elderly, anyone who has been hospitalized, has kidney disease or intestinal disease, or other chronic conditions. The Office of Dietary Supplements also includes people with dark skin, the obese and those who have had gastric bypass surgery. Aim for a total of 600 IU of vitamin D daily (including diet plus supplements) (800 IU/day if you’re over 70).
Adults over age 30 with osteoporosis or osteopenia
In this group, calcium supplementation has been shown to reduce the rate of bone loss, so supplementation is recommended.
  • Women who have reached menopause: 1200mg/day of calcium; 600 IU/day of vitamin D for women under age 70, and 800 IU/day for women 70 and older.
  • Men and premenopausal women: The jury’s still out on this, but many experts believe that 1000-1200mg/day of calcium and 600 IU of vitamin D is beneficial. For men 70 and older, 800 IU of vitamin D is recommended. 
So for some of us, it’s still important to “get milk.” Stick to the recommended intake for your age and health status and don’t forget the vitamin D!