Could dairy-free eating be eating our bones?
Could dairy-free eating be eating our bones?
By Professor Graeme Close
.
There are an increasing number of people choosing to avoid dairy in the belief that this is a healthier option or in a desire to pursue a vegan lifestyle. Many websites and bloggers claim that consuming dairy causes digestive problems, inflammation and can even increase bone loss, all of which are not supported by scientific evidence in the vast majority of people. Whilst some individuals do have a genuine allergy to cow’s milk (and therefore without doubt should therefore avoid it) many people simply avoid it regardless of symptoms. In fact, the Food Standards Agency report that almost half of people aged 16-24 claim to be dairy intolerant compared with just 8% of people over 75, whilst official statistics suggest that as little as 5% are genuinely allergic. Whilst it is perfectly possible to have a well-balanced diet avoiding dairy, there is a concern that people who just eliminate it without paying attention to what they are replacing it with run a genuine risk of drastically reducing their daily calcium intake which in the long term can have serious consequences on bone health.
Calcium is found in a variety of foods although as can be seen in Table 1, dairy based foods are an excellent source of it. It is recommended that adults consume about 1000mg per day (1300mg if you are 9-18 years old) which is easily achieved if consuming dairy products but can be more difficult from plant based foods. Calcium deficiencies can be difficult to diagnose since acute low calcium intake cannot be assessed in a blood test. This is because of the key role that blood calcium plays in muscle and heart contractions and therefore the body is excellent at maintaining blood calcium concentrations - although there is a big price to pay in doing this. The body’s reserve of calcium is in our bones and therefore when daily calcium intake is low, bones are demineralised to maintain calcium concentrations and the skeleton is weakened. Over time this can lead to stress fractures and osteoporosis. From an athletic perspective, we also know that calcium is lost in sweat which may suggest that highly active people need a greater increase in calcium than sedentary individuals. In fact, it has been shown that 1000mg of additional calcium (consumed in food products not supplements) prior to exercise is able to prevent the breakdown of bone tissue.
Table 1. Food sources of calcium. The RDA is between 700-1300mg per day.
Food and Serving Size
|
Calcium Content (mg)
|
Glass (200ml) whole, or skimmed cows milk
|
240
|
Glass (200ml) calcium enriched soy milk
|
240
|
Hard Cheese (i.e. cheddar) 30g serving
|
220
|
Yoghurt (120g)
|
200
|
Sardines (with bones) 12 tin
|
258
|
Broccoli (2 spears)
|
34
|
Kale (1 cup chopped)
|
100
|
Lettuce (1 cup chopped)
|
13
|
Typical multi vitamin / mineral supplement
|
200
|
It is therefore wise to pay some attention to calcium intake especially in highly active people and try to assess your daily intake. If you are going to embark upon a vegan diet, or dairy free diet, it is important to ensure that calcium is replaced (for example calcium enriched soy milk). However, please remember that contrary to what is often written by nutrition gurus, there is no health advantage of going dairy free unless you have a genuine allergy which should be diagnosed by a qualified medical professional. So, let’s give some respect back to this crucial mineral and ensure that we are doing everything we can to build and maintain a strong skeleton.
Good luck
Graeme