Plant-based drinks like oat, soya, almond and coconut "milk" have gone from niche to mainstream in UK kitchens, often marketed as the healthier or more natural option. The reality, according to the NHS and the British Heart Foundation, is more balanced: unsweetened, calcium-fortified plant-based drinks can sit in the same food group as dairy milk and make a perfectly good alternative, but unfortified versions generally fall short of cow's milk on several nutrients. This article looks at what actually differs nutritionally, whether "dairy-free" really means healthier, and what to drink if you're lactose intolerant.
Who this is for
This is for you if you've stood in the milk aisle wondering whether switching to oat or almond milk is a genuine health upgrade, or if you're lactose intolerant and trying to work out what actually covers the nutrients cow's milk would normally provide.
What's actually in cow's milk compared with plant-based drinks?
Cow's milk is a naturally strong source of protein, calcium, iodine, and vitamin B12. Among plant-based drinks, soya milk has the most similar protein content to cow's milk, at roughly 7 to 8 grams per serving, while oat milk typically provides around 3 grams and almond milk as little as 1 gram, since almonds and oats are simply not protein-dense foods to begin with.
Iodine is the nutrient most easily overlooked. A 200ml glass of cow's milk provides roughly 85 micrograms of iodine, largely because of fortified cattle feed, while unfortified plant-based drinks typically contain only around 2% of that amount. This matters because iodine is important for thyroid function, and UK survey data has found iodine deficiency in a meaningful proportion of women of reproductive age, a group already considered at higher risk.
Are plant-based alternatives actually healthier?
Not automatically. The British Heart Foundation's guidance is direct on this point: there isn't a strong nutritional reason why any one type of milk is "best", and it comes down to the nutrients in each drink and whether you're getting them from elsewhere in your diet. Two things are worth checking on any plant milk carton before assuming it's the healthier pick.
First, added sugar. Flavoured and sweetened plant milks often contain more sugar than plain cow's milk, whose natural milk sugars are not the type of sugar people are generally advised to cut back on. Choosing unsweetened versions avoids this issue entirely. Second, fortification. A plant milk fortified with calcium, vitamin D, riboflavin, vitamin B12 and iodine can genuinely stand in for dairy nutritionally, while an unfortified one, including many "premium" or organic plant milks, will not.
What should someone who is lactose intolerant drink?
If dairy milk causes symptoms, NHS guidance points to a few reliable options. Lactose-free cow's milk, which has the lactase enzyme already added, gives you the same nutritional profile as regular milk without triggering symptoms for most people. Alternatively, calcium-fortified soya or oat milk is a widely available substitute, though it's worth checking the label for added calcium specifically, since not all plant milks include it by default.
Since cutting out dairy can reduce your calcium intake, the NHS also suggests other calcium sources worth including regularly: dark green leafy vegetables, canned fish such as sardines or salmon eaten with bones, and calcium-fortified orange juice or breakfast cereal. If you're removing dairy from a child's diet, or you're concerned about calcium intake more generally, asking a GP for a dietitian referral is a reasonable next step.
Neither cow's milk nor plant-based milk is universally healthier: cow's milk naturally provides more protein and iodine, while unsweetened, calcium-fortified plant milks can sit alongside dairy as a genuinely equivalent choice. Unfortified plant milks generally fall short on calcium, iodine and B12 unless you're getting those nutrients elsewhere. If you're lactose intolerant, lactose-free cow's milk or a calcium-fortified plant milk are both reasonable choices, alongside other calcium sources like leafy greens and canned fish. If you have specific concerns about your diet, a GP or registered dietitian can advise further.
Questions people often ask
Not automatically. Oat milk has less protein and, unless fortified, less calcium and iodine than cow's milk. An unsweetened, fortified oat milk can be a reasonable alternative, but "healthier" depends on what you need from your diet overall.
It depends on the type and whether it's fortified. Soya milk has a protein content closest to cow's milk. Calcium is only reliably present in plant milks that are specifically fortified, so it's worth checking the label rather than assuming.
Lactose-free cow's milk, which has the lactase enzyme added, or a calcium-fortified soya or oat milk are both commonly recommended options. Checking that a plant milk is specifically calcium-fortified is important if it's replacing dairy in your diet.
Not inherently. Unsweetened, fortified dairy-free alternatives can be a genuinely good substitute for dairy, but unfortified or sweetened versions often provide less protein, calcium and iodine than cow's milk.
This article is for general information only and is not a substitute for professional medical advice. If you are concerned about a specific symptom, please see a GP or other qualified healthcare provider.