We asked Dr Robert Heaney, an internationally recognised expert in the field of bone biology and calcium nutrition, the most frequently asked questions about bone and supplementation. He has studied osteoporosis and calcium physiology for over 45 years, and has published more than 300 original papers, chapters, monographs and reviews in scientific and educational fields.
IS POTASSIUM NECESSARY FOR BONE HEALTH?
DR HEANEY: Potassium is important. It’s important for everything in our body. It’s important for blood pressure control. It’s important for reduction of risk of kidney stones. It’s important for bone health.
Like all nutrients, it acts in all tissues, but we don’t have randomised controlled trials that compare the effects of low- and high-potassium diets on bone status. So we don’t have that kind of evidence, but the epidemiological evidence, the observational study evidence, indicates that yes, it’s important.
WHAT’S THE CONNECTION BETWEEN CALCIUM AND VITAMIN D IN BONE HEALTH?
DR HEANEY: Calcium is the principal mineral in bone, and if you don’t get enough calcium you either can’t make enough bone during growth or you tear down your bone as an adult in order to make up for what your diet doesn’t provide. Now vitamin D comes into the story, because vitamin D is necessary to help the body regulate calcium absorption so that you use your food calcium with maximum efficiency.
DOES VITAMIN D DEFICIENCY PUT WOMEN AT A HIGHER RISK FOR FALLS AND BONE FRACTURE?
DR HEANEY: Vitamin D-deficient women are much more likely to fall and break a bone. In a marvelous randomised trial conducted by Heike Bischoff five or six years ago, elderly south German women were randomised to receive either calcium alone or calcium plus vitamin D. There was a 50% reduction in fall risk in the vitamin D-treated group compared with the group treated with calcium alone. This is not to suggest that calcium isn’t important, but it’s not important for falls, whereas vitamin D is.
We don’t know for sure how vitamin D is working here, but the effect is very evident and that may well be one of the most important reasons why it reduces fracture risk. If you don’t fall, you’re less likely to break something.
DOES SMOKING INCREASE WOMEN’S RISK FOR BONE FRACTURES?
DR HEANEY: Yes, smoking does increase the risk of fracture. We don’t know why. We have lots of theories and some of them are at least partly true, but we don’t have a good, solid explanation. However, the fact remains that smokers are more at risk for fracture.
WHICH IS BETTER: CONSUMING DAIRY PRODUCTS OR TAKING SUPPLEMENTS FOR STRENGTHENING BONES?
DR HEANEY: Dairy foods are far and away better than supplements. Supplements have a role, but that role is defined by the name itself. They should supplement an already good diet. They are not a substitute for a good diet.
WHEN SHOULD WOMEN START PRO-ACTIVELY PREVENTING OSTEOPOROSIS?
DR HEANEY: Women need to start in adolescence. They’re building their peak bone mass then. Half of the bone they will have as an adult comes in between, say, 12 and 19, and then there’s a further consolidation to age 30 – at that point, the window of opportunity is just about closed.
Then, a woman has to optimise what she’s got. She’s got to hold on to it as best she can, but she needs to be active while she is building it. Think of a three-legged stool. Where our bones are concerned, the three legs required are an active exercise programme, good nutrition, and normal hormonal status. So amenorrhoea, athletic amenorrhoea, being too thin because of a lot of exercise, anorexia nervosa, the other eating disorders – they’re all very bad for the skeleton
THE ROLE OF D VITAMINS
Using his own data, Dr Heaney showed that vitamin D3 (cholecalciferol) produced far superior results to vitamin D2 (ergocalciferol) in terms of raising and sustaining actual blood levels of active vitamin D, but also that D2 could be used to treat vitamin D deficiency just as easily as D3. Note that vitamin D2 is from a vegetarian source, while D3 is always from an animal source, either lanolin or fish liver oil.
Dr Heaney also showed that the risk of toxicity is extremely low – so low, in fact, that it’s hard to put a precise number on what constitutes a toxic dose. Although he emphasises that he’s not advocating sky-high doses, Heaney suggests that, at a minimum, you’d need to be taking around 30 000 IU a day for a long period of time before toxicity would become an issue.
Heaney has stated that a healthy person metabolises 3 000 – 5 000 IU of vitamin D per day. Dr Heaney passed away in 2016. Remembering Dr Heaney: http://www.creighton.edu/heaney/