Q. I have a two-year-old son who is lactose intolerant. How do goat's milk and soy milk compare nuritionally to ordinary cow's milk? And is he likely to grow out of this?

A.  All three milks are similar nutritionally, being good sources of protein for growth, B vitamins for nerves and digestion and bone-building calcium (provided you choose calcium-fortified soy drinks, which most are - read more below).

But both cow's and goat's milk contain about 4 per cent lactose so neither is suitable for your son. But you can purchase low-lactose and lactose-free cow's milks in fresh or long-life forms at the supermarket if he likes their flavour. Look for brand names such as Zymil.

If he doesn't like milk, hard yellow cheeses (cheddar, parmesan)  have very little lactose but still have all the other nutrients of milk.

Soy milks and other plant mylks

There are two types of soy milks and this is important to know this as their calcium content is quite different:

1. Pressed soy milks - these are made from soy beans and are as close to the natural bean as possible. Usually they are NOT fortified with added calcium.

2. Composite soy milks from soy protein concentrate or isolate - these have added oil, sugars, thickeners, vitamins and minerals including calcium so they closely match the profile of milk. They have the same calcium as cow's milk - around 120 mg per 100 mLwhich translates to about 300 mg per glass. These are the best choices for your son. However, he may not like their taste nor are they as 'natural' as the pressed milk. It's something to think about.

Getting enough calcium

For a growing toddler, the problem is to get sufficient calcium for his bones and teeth at this age. Milk, cheese and yoghurt are the richest sources of calcium - and their calcium is well absorbed. He needs some 400 mg of calcium a day which would normally come from two glasses of milk OR two tubs of yoghurt OR two thick slices of cheese.

He will ingest small quantities of calcium from sardines or salmon with their small edible bones and from certain vegetables (broccoli, spinach) and nuts (almonds, sesame seeds). But kids generally don't eat enough of these foods nor is their calcium well absorbed.

A calcium supplement can help but it's not something I like to recommend for young ones. I much prefer them to get their nutrition from food where there's little chance of overdose and the nutrients are present in the right form in combination with other complementary things.

Will your son grow out of lactose intolerance?

This all depends on how he acquired the intolerance in the first place.

If he developed it following a bout of gastroenteritis or food poisoning, his digestive tract will recover after 4 to 6 weeks and he should be able to resume his usual diet including milk and yoghurt.

However as you didn't mention anything about this, I suspect he's had this for a while

Many racial groups are lactose intolerant and don't consume milk after the age of 5 or thereabouts. If your family has Asian, African or Middle Eastern inheritance, then it's quite likely that they won't be able to drink much milk past childhood. You'll find cultured (fermented) dairy products in place of milk - things like yoghurt, soft cultured cheeses, kefir or lassi drinks. The bacteria used to make yoghurt and cheese actually break down the lactose from milk so these products are better digested and tolerated.

The bottom line

Remember that there are degrees of severity with lactose intolerance - over time, he may be able to manage small quantities of regular milk, especially if drunk with a meal. Research shows that many people with the problem can and do drink milk regularly without any pain or symptoms. While they don't gulp down a milkshake or a tall glass of milk on an empty stomach, they can certainly manage milk with their tea or coffee or milk with a bowl of cereal.