The Healthy Food Guide team believe that making small diet and lifestyle changes brings the best long-term gains. We look at the science behind the headlines and promote a balanced way of eating.

Lactose is the sugar in milk and milk products (it’s one of the FODMAPs).

‘However, lactose intolerance can occur independently of other FODMAPs if you’re deficient in lactase, the enzyme that breaks down lactose to enable its absorption,’ says HFG expert and dietitian Jennifer Low. ‘When gut bacteria ferment unabsorbed lactose, bloating results, and is often accompanied by nausea, diarrhoea and abdominal cramps.’

A stomach bug can trigger a temporary bout of lactose intolerance, and production of the enzyme lactase can slow as we age. Lactose intolerance is also more common among certain ethnic groups, particularly in people of Asian, African and South American descent. Your GP can diagnose suspected lactose intolerance with an elimination diet and/or a hydrogen breath test.

How to treat it:


1. Limit or avoid foods

that contain lactose – but you may not need to cut it out altogether as many people find they can tolerate some lactose without symptoms. ‘This can be a process of trial and error, as most lactose-intolerant individuals still produce some lactase, and the amount they produce dictates just how much lactose they can consume without experiencing discomfort,’ explains Jennifer.
The amount of lactose contained in dairy foods varies considerably. In general:

Milk and custard contain large amounts

Yogurt contains medium amounts (much is fermented by the bacteria used in yogurt-making)

Soft cheeses and cream contain small amounts

Hard cheeses and butter contain virtually none


2. Choose lactose-free

milk and yogurt, and soy, rice, oat and almond milks, which are naturally lactose free. Go for unsweetened products that are fortified with calcium.

3. After removing or reducing

lactose, bloating should quickly subside. ‘Once you’ve been symptom free for a while, it’s a good idea to reintroduce lactose to see if you can tolerate it again,’ says Jennifer, ‘as the calcium in dairy is generally better absorbed than that from non-dairy substitutes.’