Milk consumption in most of the people can lead to bloating, cramps, diarrhea and nausea.

Most adults can’t digest milk

It is surprising since most of us after childhood still drinks milk.

Bad reactions to drinking milk is not a response of immune system, so it is not food allergy. It’s about digesting the main sugar – lactose. To properly digest lactose you need to produce enzyme called lactase. Normally humans stop produce this enzyme between second and fifth year of life. Without producing it, undigested lactose from milk is fermenting in the colon and produce gas, which can cause unpleasant symptoms, such as cramping, bloating, nausea and even diarrhea.

Ancestry matters

Less than 40% of people in the world retain the ability to digest milk after childhood.

Milk can be digested after childhood in about:

90% of northern Europeans (the world’s highest percentages of milk tolerant people especially live in the Netherlands, Ireland and Scandinavia),

50% of Mediterranean peoples,

25% of African and Caribbean peoples,

5% of Asians,

0% of Native Americans.

Scientific base

Now we know that lactose intolerance is dominant. In fact, globally it is unusual to digest milk after childhood properly. But how can we know if we can drink milk without the risk of unpleasant symptoms? Lets look closer to gene which encodes lactase protein – enzyme required to digest sugar from milk.

It is called MCM6 and was found an on/off switch for the LCT (gene encoding lactase).



Possible results:

GG

You are likely lactose intolerant as an adult.

Lack of lactase enzyme causes inability to drink much milk in adulthood without risk of unpleasant symptoms, such as cramping, bloating, nausea and diarrhea.

What now?

Remember, you can still be able to digest milk. Observe Yourself and try to find out if drinking more than one glass of milk per day works fine for Your body. Clinical symptoms typically appear within 30 minutes, but remember that it may take up to two hours.

Because of environmental reasons e.g. your gut bacteria or other unknown genetic effects reasons, you can still be able to digest dairy.

AG & AA

You are likely lactose tolerant as an adult.

You are producing high lactase enzyme levels, which enables you to digest dairy.

What now?

If you like milk, drink it!

Keep in mind that you can still be lactose intolerant due to other environmental factors for example your gut bacteria or other unknown genetic effects reasons.

The mutation in genome that allows to stay milk drinker into adulthood appeared about 7,500 years ago in dairy farmers who lived between the central Balkans and central Europe.

Genetic basis of lactase production in Africans was previously unknown, although 25% of Africans tolerate lactose. There may also be other, unknown genetic effects that allows to digest milk sugars than SNP described here.

How to avoid lactose-containing products?

Percentage of lactose content in unprocessed milk:

human milk – 9%,

cow milk – 4.7%,

goat milk – 4.7%,

buffalo milk – 4.89%.

Plant-based milks (e.g. soy, rice, almond, coconut milk) are lactose free.

Dairy products

Lactose is a water-soluble substance, not found in the fat-based. Dairy products that are ‘reduced-fat’ or ‘fat-free’ may have slightly higher lactose content.

Butter

In butter-making process lactose is largely removed, however will still be present in small quantities. Clarified butter contains very little lactose and is safe for lactose-intolerant people.

Yogurt

Yogurt contains lactase from bacterial cultures, so can be better tolerated than milk. Greek yogurt is better tolerated, contains less lactose.

Cheeses

Hard cheeses, and soft-ripened cheeses are better tolerated (contains less lactose because of making process), but total amount of milk sugars varies depends on the type of cheese.

Nondairy products

It is popular to add lactose to many processed products such as meat, margarines, potato chips or protein powders and shakes.

I am lactose intolerant, but I like drinking milk. What can I do?

It is possible to use lactase supplements. In many countries without prescription you can buy tablets which contains this enzyme. Try not to use then on empty stomach, because too much acid can inactivate it.

Scientifically speaking MCM6 gene area is connected with physiological activity of the lactase-phlorizin hydrolase (LPH) in intestinal cells after weaning. LPH hydrolyzes lactose into glucose and galactose.

Are You lactose-tolerant? Share Your opinion with others.