The health benefits of good old-fashioned cow’s milk

How does cow's milk weigh up against its alternatives?
How does cow's milk weigh up against its alternatives?

Do you want regular milk with that? The question that accompanies every modern coffee shop order. Depending on how trendy the establishment is, whispering “cow’s milk” can feel like an illicit act.

According to Starbucks, the UK is the “alt-milk” capital of Europe, with non-dairy alternatives making up 16 per cent of its beverage sales in 2023.

Reasons of taste, concern for the environment and animal welfare may all form part of your decision-making process. But what of health?

In the northern hemisphere, where we have a long history of bovine husbandry, it’s a key component of our diet.

“It’s not that we have to drink it or that we can’t survive without it, but if you were to take it out of a typical British person’s diet you would need to think carefully about where else you would get the nutrients that milk provides,” says nutrition scientist Bridget Benelam of the British Nutrition Foundation.

Girl drinking a glass of milk
Drinking milk can be important to our development and health - Getty Images/Sam Edwards

These are nutrients that can be hard to get elsewhere and are important to our development and health – “which is something you need to consider if you are switching away from dairy,” says Benelam.

So what are the key vitamins in your glass of cow’s milk and how does it compare with the alternatives?


Milk is a rich source of two types of protein: casein and whey. Casein makes up 80 per cent of the proteins in milk and is noted for its ability to increase the absorption of minerals, such as calcium and phosphorus. Whey, which makes up 20 per cent, is noted for being rich in amino acids such as leucine, isoleucine, and valine.

“Compared to the alternatives, it’s generally a better source of protein; there’s more protein by around 3.4 grams per 100 ml,” explains Duane Mellor, a dietitian at Aston University in Birmingham. “The only one that gets anywhere close is soy milk. Oat is about 2g. Rice milk and almond milk are a lot lower.”


This nutrient is needed to build and maintain healthy bones, but it also helps keep muscles, nerves and teeth healthy. According to the British Nutrition Foundation, adults need around 700mg of calcium per day.

“Dairy products are one of the main sources of calcium in the UK diet. A 200ml glass of skimmed milk, for example, will provide 34 per cent of an adult’s daily need for calcium,” says Benelam.


One of eight B vitamins, B12 is also known as cobalamin and is key to a healthy metabolism. A deficiency of B12 can also cause megaloblastic anaemia, a blood condition that makes people tired and weak.

“This is also a vitamin that becomes harder to absorb as we get older and which we can only get from animal foods,” says Mellor.

One glass (250 ml) of milk provides approximately 50 per cent of the recommended daily allowance.

Woman pouring milk on cereal in kitchen
Drinking cow's milk can add calcium to our bodies, great for keeping muscles and nerves healthy - Getty Images/Betsie Van Der Meer


The body needs iodine to make thyroid hormones, which in turn control the body’s metabolism and many other important functions.

“In south-east Asia they source their iodine in their diet, mainly from seaweed,” says Mellor. But traditionally, in the northern hemisphere, we have found it in dairy products. “Other countries add iodine to their salt, but we don’t in the UK,” adds Mellor.

A 200ml glass of milk provides 34 per cent of the World Health Organisation’s recommended iodine intake for adults a day.


Remember the days of untreated milk in glass bottles with a yellow, creamy top? “That colour is riboflavin,” says Mellor.  Also known as B2, it has a number of roles. Its main link is to metabolism and energy release.

“If you don’t have enough you can get ariboflavinosis, a condition that leads to cracking in the corners of the mouth and can change the textures of the tongue. Riboflavin is the most abundant and bioavailable B-vitamin present in milk.

However, it is highly sensitive to degradation. Riboflavin content may vary depending on processing or the type of milk; one study found that commercial milk in summer contained about 20 per cent more riboflavin than milk in winter, due to a change in feed from corn silage to pasture.

How plant-based milks measure up

While calcium, B12, iodine, riboflavin and vitamin D are frequently added to plant-based milks, fortification varies greatly between brands. And if it is organic, then they’re not allowed by law to fortify it. “That’s a strange quirk,” says Mellor.

He recommends always scrutinising the labels to see what levels of vitamins have been added.

“I’d look for ones that are fortified with calcium, riboflavin, iodine and ideally vitamin D. To get as close to cow’s milk as possible in terms of replacing those vitamins, look for 15-20 per cent minimum per 100mls (of the amount in cow’s milk).”

Dairy milk is not, in general, a good source of vitamin D, which you do get added in some plant milks.

A 2023 study by the University of Minnesota found that compared with cow’s milk, only 12 per cent of the milk alternative products contained comparable or greater amounts of all three nutrients studied: calcium, vitamin D, and protein.

Also look out for added sugar. Lactose is the sugar that naturally occurs in milk – it is the main carbohydrate in milk and provides the slightly sweet taste that is present in plain, unsweetened milk.

“In cow’s milk the sugar is only lactose, which is slowly digested, whereas plant milk alternatives can be sweetened with fruit juice or added sugar,” says Mellor. “Added sugars tend to be digested quickly and are therefore thought to be less healthy.”

A common problem with vegan substitutes is that they are often functionally similar, but not nutritionally equivalent.

“Jackfruit is an example. In terms of texture it’s a good substitute for meat, but in terms of nutrition it is not great at all. Similarly with vegan cheese, you’re getting the functionality but not the protein or interesting fatty acids.”

In milk terms this means that you might be able to achieve the same creaminess from an oat or potato milk, but not the same nutritional content, unless your milk is heavily fortified.

What if I’m lactose intolerant?

Northern Europeans have adapted, through raising cattle and drinking milk for several thousand years, to retain the lactase enzyme that digests lactose. Even so, in the UK, around one in every 10 older children and adults is still thought to have a genuine lactose intolerance.

Someone adding milk to a cup of tea
Like with anything, drinking cow's milk should be part of a balanced diet - Getty Images/grandriver

However, a 2021 University of Bristol study found that thousands of infants are being wrongly diagnosed with an allergy to cow’s milk. “There are many things that can cause us to have uncomfortable symptoms,” says Benelam of misdiagnosis. “It might be that people are avoiding dairy when they don’t need to.”

“It’s a bit tricky to specify the symptoms of lactose intolerance, as gastro-intestinal symptoms will vary from person to person and involve different amounts. It can be a subtle condition,” says Benelam.

Dairy negatives

But dairy, including full-fat milk, is relatively high in fat – is that a worry? “Saturated fat is something we generally advise people to cut back on and replace with unsaturated fat, but there is evidence that suggests saturated fats in dairy such as milk and cheese may not raise cholesterol in the way you might expect.”

The fat content of milk isn’t that concerning to Mellor: “Most people consume about a third of a pint of milk a day, in their tea or on their cereal. That’s not a significant amount of fat. It’s the other foods in their diet that are higher in saturated fats which are worse.”

However, as in all things, moderation is key. Drinking three or more glasses of milk has been linked to an increased risk of bone fractures in women (the reason is not entirely clear, but d-galactose, a breakdown product of lactose, has been linked to oxidative stress and inflammation), while excess calcium from milk and other foods may increase the risk of prostate cancer, alongside concerns about saturated fats.

“The overall health benefits of drinking milk are probably on the neutral side,” says Mellor. “Where you definitely get more benefits is with the fermented milk products, yoghurts and some cheeses.”

Which cow’s milk is best?

Even the nutritional content of your cow’s milk can vary greatly. “Data shows that the time of year can affect the nutritional value of your milk,” says Mellor. “There tends to be more fats in it when the cows are better fed; you get richer milk when there’s more grass in the early summer.”

It also varies from cattle to cattle. “We know Jersey milk is higher in fat and creamier than Holstein milk. Although the health benefits haven’t been proven.”

Pasteurisation is used in milk to lengthen shelf-life and reduce the risk of foodborne illnesses. “Nutritionally speaking there isn’t a difference between pasteurised and unpasteurised,” says Benelam.

Milk bottles in a crate
Milk varies all depending on the cattle - Getty Images/Johnny Greig

However, when you’re choosing between full-fat, semi skimmed milk and skimmed, there are slight differences. “You get a bit less vitamin A with skimmed milk as it is fat soluble and so will be in the fatty component of the milk.”

The other key vitamins are in the watery component of the milk: “So you don’t lose out on nutrients by choosing reduced-fat milk,” says Benelam.

Whole cow’s milk has more calories and saturated fat compared with both semi-skimmed and plant-based alternatives.

Switching from full-fat milk to semi-skimmed milk in tea (up to five cups a day) is likely to save the average person less than 50 kcal per day. This means, even when considering calories and energy, the effect of reducing fat is minimal.

Quantity is key. “Certainly if you’re drinking milky drinks like lattes and hot chocolates, there will be a difference in terms of calories and fats. Choosing reduced-fat milk for most people is a good idea,” says Benelam. Conversely, skimmed milk can spike your blood sugar levels due to faster absorption. “Like so many things around diet, it’s about balance.”