Q: What about calcium?

A: This question is often asked as a result of dairy industry sales hype suggesting that milk is the best protection against osteoporosis. There is good evidence that calcium intakes above 500 mg per day are important for developing maximum bone mass in adolescence and that intakes up to 1000 mg per day may be beneficial for people on typical Western diets. Such intakes can be readily achieved on vegan diets by including foods naturally rich in calcium such as kale, spring greens, tofu set with calcium, almonds and tahini. Even the humble orange can play its part, with a medium-sized orange providing about 60 mg of calcium along with other valuable nutrients such as vitamin C, folate and potassium. If such foods are not to your taste in large amounts, calcium-fortified plant milks, juices and breads or even a simple calcium supplement can be used to boost calcium intakes.

Evidence that milk consumption as an adult reduces fracture risk or improves bone density is sparse to say the least. Studies of calcium supplementation for up to four years do show a benefit on bone density and fracture risk, particularly if accompanied by a vitamin D supplement. No studies on calcium supplementation have been carried out for more than four years. The few short-term studies on increased dairy consumption suggest that the effect of calcium from dairy is less than that of calcium from supplements. Population-based studies have mostly found no association of adult dairy food consumption with fracture risk, with just one prospective study suggesting a beneficial effect and a more recent and larger study suggesting an adverse effect.

There is, however, good evidence that fruit and vegetable intake protects bones and reduces fracture risk, with green leafy vegetables such as lettuce, broccoli, spinach and kale, topping the list of protective foods for postmenopausal women not on HRT. Such foods reduce calcium losses and promote bone building. In contrast, salt consumption and excessive protein intake increase losses. Variation in calcium losses accounts for 50% of the variation in calcium balance in adults while calcium intake and absorption account for only 25%. The best dietary insurance policy for bone health is to reduce calcium losses while at the same time getting an abundant calcium intake of around 800 to 1000 mg per day. Foods such as milk, and especially cheese, increase losses at the same time as providing calcium and are therefore not an ideal source of calcium.

Even if dairy products were an effective source of calcium, they could not be recommended for health as they are an exceptional source of saturated fat. An adult getting 1000 mg of calcium from cheddar cheese would be getting a staggering 30 grams of saturated fat and losing more than half the extra calcium through increased losses. Low fat dairy products allow health-savvy individuals to avoid the unwanted fat but do nothing to protect the population as a whole since the dairy industry ensures that the fat removed from the low fat milk turns up elsewhere in high fat cheeses, buttery pastries and biscuits, ice cream, pizza, convenience foods and ready meals. Once the cow is milked, someone ends up eating or drinking the dangerous dairy fat.