Doctors recommend that babies consume nothing but breast milk up until their sixth month. Beyond that, do humans really need dairy? Many studies have been conducted over the years with varying results as to how dairy affects your diet and health. We break down the research so you can decide if it’s something you really need.

The Good

Curiously, humans are the only species that consume milk from other animals. Proponents say that it’s because dairy products give many health benefits, from bone-building to weight loss. While there is still no conclusive evidence that shows how dairy affects your diet for weight loss (research suggests that it’s a result of reduced overall calorie consumption, not consumption of dairy alone), there are still other benefits supported by science:

Milk gives you a nutrient boost. A cup of milk contains about a quarter of the recommended daily intake of calcium and Vitamin D. It also contains plenty of other nutrients like riboflavin, potassium, phosphorus, and Vitamin A, among others, plus 8 grams of protein.

It’s good for bone health. The mix of calcium and Vitamin D in dairy helps strengthen bones and may protect you from problems like osteoporosis later in life. The recommended calcium intake for adults is about 1,000 mg per day—that’s equivalent to three cups of milk. Do note that milk isn’t the only source of dairy, and that dairy isn’t the only source of calcium and Vitamin D. (More on that later.)

It may be good for heart health. A study published in the British Journal of Nutrition found that men who consumed more fermented dairy products had a lower risk of coronary artery disease. Keep in mind that these dairy products are those that have probiotics, or the live microorganisms that help keep the gut microbiome balanced.

The Bad

As with most things, there are conflicting studies when it comes to how dairy affects your diet and health. Some of the undesirable effects it may have are:

It may do funny things to your tummy. It’s estimated that up to 90% of Asians are lactose intolerant. This means that 9 out of 10 of us can’t properly break down lactose, or the sugar found in milk. Some develop this intolerance later in life. Lactose intolerance can cause bloating and other stomach problems like diarrhea.

It may be linked to heart disease… but this may only be true when milk is consumed in excessive amounts (about a liter a day). The American Heart Association still recommends limiting milk consumption to fat-free or low-fat versions, but studies so far have not shown a link between dairy product consumption and heart disease. It seems safe to consume full-fat dairy as long as you don’t overdo it. (Or, as mentioned earlier, choose fermented dairy, which is better for your heart.)

It may affect breast milk of lactating women. Does your baby seem extra fussy after breastfeeding? If you drink cow’s milk, the proteins in it may be affecting your own milk, making it harder for your baby to digest. You may want to eliminate cow’s milk from your diet while you’re nursing and see if it has any effect.

It may sabotage special diets. You may be wondering how dairy affects your diet like keto. Dairy has a good amount of protein, so it should be included in the list of edibles for keto, right? Unfortunately, milk contains sugar (lactose) and plenty of carbs—both of which you have to drastically reduce when you’re on keto.

If you’re a dairy lover on keto, all is not lost. Ideal dairy products for those on keto are butter, hard and soft cheeses, cream cheese, sour cream, and Greek yogurt. (Note that the nutritional content of these products varies from that of milk.)

The Bottom Line

Dairy products are a great source of calcium, protein, and Vitamin D. But if you don’t particularly enjoy the taste of dairy, then you can get these nutrients from plenty of other food sources. Get calcium from nuts, legumes, and greens; protein from eggs and lean meats like chicken and fish; and Vitamin D—a nutrient that is typically added to dairy products—from fortified cereals.

If you do enjoy dairy products but are lactose intolerant, choose those with probiotics. These may be easier on your tummy as they contain live microorganisms that can aid in digestion. You can also go for milk substitutes such as soy milk and almond milk, keeping in mind that the nutritional content isn’t the same as dairy milk; they typically have less protein. If you do decide to make dairy a regular part of your diet, consume it in moderate amounts in conjunction with other nutrient-rich whole foods. Add a cup of low-fat milk to your morning cereal, or snack on some Greek yogurt. (Just take care to avoid those with added ingredients like honey to keep the sugar content low.) Visit Healthy Options for a range of healthy dairy products and alternatives.