Dairy allergy: what to avoid, and how oat, almond, soy and coconut milk compare

If you're avoiding dairy because you want to, a mistake means a slightly disappointing meal. If you're avoiding it because of an allergy or intolerance, it can be a lot worse. This post is written for the second group — the people for whom "probably fine" isn't good enough, although anyone cutting dairy will find the label-reading useful.

The single most important habit is this: trust the ingredients list, not the marketing on the front. A carton can say "plant-based" in large letters and still carry a milk derivative in the small print, and a dish can look completely dairy-free and arrive finished with butter. Read the ingredients list carefully.

The names that all mean dairy

Manufacturers have a lot of words for milk, and not all of them look like milk. If you see any of these, the product contains dairy, regardless of what the front says: casein and caseinate (milk protein), whey (the liquid fraction), lactose and lactalbumin, and the more obvious milk solids, milk powder, ghee, and curd.

Casein and whey are the two that catch people out most often, because they turn up in foods you'd never think to check — protein bars, processed bread, "non-dairy" coffee creamers (yes, really), and some brands of dark chocolate. Learn those two words cold and you'll catch most hidden dairy on sight.

Another recent trend, especially in India, is marketing a product as lactose free. If you are vegan, either by choice or by compulsion, this is very tricky. Lactose free, especially for products such as milk, curd/yogurt, ice cream, would mean that the lactose content is less than a certain percentage (0.1%), but it still contains dairy. For anyone with a dairy allergy, this can mean a trip to the hospital in case of a bad reaction.

Where it hides when you're not looking

Dairy has a habit of appearing in savoury foods that have no business containing it. The usual suspects: bread and pastry glazes, flavoured crisps and snacks, instant soups and sauce sachets, chocolate labelled "dark" (which is often only darker, not dairy-free), and restaurants serving mashed potato and creamed or buttered vegetables, which are almost always finished with butter or cream in the kitchen even when the menu doesn't say so.

The rule that has saved me the most trouble: if a dish is described as creamy, glossy, or rich and you didn't add anything to make it so, ask what's making it that way before you eat it. Specify multiple times that it should not contain any butter, milk, milk derivatives or even honey.

The four plant milks, compared

There's no single best plant milk. Each one is good at something and bad at something else, and the right choice depends on what you're using it for and what else you're avoiding.

Oat milk is a popular choice, although availability may be limited in some countries. Creamy, neutral in flavour, and it foams well enough for coffee. It's higher in carbohydrate than the others and bakes beautifully. The catch: oats are naturally gluten-free but are very often processed alongside wheat, so if you're also avoiding gluten, it has to say "gluten-free" on the label, don't assume.

Almond milk is thin, light, and low in calories, which makes it pleasant in cereal and smoothies but underwhelming in coffee or cooking, where its wateriness shows. It's also low in protein. And the obvious disqualifier: it's off the table entirely if tree nuts are one of your problems.

Soy milk is the closest to cow's milk on protein and the most reliable in cooking — it holds up in sauces and doesn't split as readily as the others. Its flavour is more distinctive, which some people like and some don't. Worth remembering that soy is itself one of the major allergens, so it solves a dairy problem only if soy isn't a second one.

Coconut milk comes in two forms worth keeping straight: the thick tinned kind for cooking, and the thinner carton kind sold for pouring. As a drinking milk it's low in protein and carries a distinct coconut flavour, but it's naturally free of dairy, soy and gluten, and despite the name it's a fruit rather than a tree nut. So it's usually fine if you're avoiding almonds or cashews, although if you have a diagnosed coconut allergy then it is not. Where it really earns its place is cooking, holding up in a sauce without splitting better than any of the others.

What you give up, and how to get it back

Here's the part the marketing skips: cow's milk naturally carries protein, calcium, and often added vitamin D, and plant milks don't automatically match that. Most are fortified to get there. Calcium and B12 are added back in during production, but not all products follow the process. The cheaper or more "natural" a carton markets itself, the more likely it is to have skipped fortification.

So two habits when you buy: check that the carton explicitly says it's fortified with calcium and B12, and buy the unsweetened version unless you have a specific reason not to, because the sweetened ones carry a surprising amount of added sugar for something you'll pour on cereal every morning.

None of this is complicated once it's habit. It's really just two simple moves. Read the back of the pack, and ask what's making a dish rich before you eat it.