Lactose Intolerance: Why Can Only Some People Tolerate Dairy?

Why Can Only Some People Tolerate Dairy

Milk is really nutritious. It contains calcium, protein, vitamins B2 and B12, and vitamin D; and it is considered to be somewhat of a nutritional powerhouse. For those populations that do not have easy access to fresh vegetables or meat, milk and milk products provide a great deal of nutrition. However, according to the National Institutes of Health (NIH), 65 percent of the human population suffers from lactose intolerance. More than half of the world’s population cannot properly digest the lactose (sugar) found in dairy products.

Interestingly, what science has uncovered is that humans are not inherently lactose intolerant. In fact, humans actually developed lactose tolerance as they evolved. All humans are born with the ability to digest lactose. But, as we age, we produce less and less of the enzyme lactase needed to digest the sugar lactose, resulting in lactose intolerance. The question remains: Why can only some of us tolerate dairy while 65 percent of us cannot?

Let’s explore an evolutionary answer to that question. Thousands of years ago, as different populations began to farm and domesticate animals for food, humans began to acquire the ability to digest lactose from childhood into adulthood. This tolerance varies based on geography and ethnic origin. Where conditions weren’t conducive to herding, like in Asia and parts of Africa, populations did not develop the ability to digest lactose. According to the NIH, 90 percent of individuals of East Asia descent are lactose intolerant.

As mentioned earlier, lactose intolerance is the inability to properly breakdown lactose, the sugar found in milk. This sugar is not only found in cow’s milk, but milk from all mammals: cows, sheep, goats, and humans. When the sugar is not broken down, it passes into the colon where it mixes with bacteria and ferments. The resulting symptoms include gas, bloating, discomfort, and diarrhea. Although the condition is not serious, it is uncomfortable and embarrassing.

Managing these symptoms does not require a complete avoidance of all dairy products. Hard, aged cheeses like cheddar and parmesan are generally fine. Enzymes that are used in the cheese-making process break down the lactose over time; and after about six months, very little lactose is left. Greek yogurt and full-fat yogurts, butter, and kefir are additional options that have little to no lactose and can be tolerated more easily.

Many milk alternatives are available. Rice milk, soy milk, and lactose-free milk have been available in the grocery stores for some time. Now with the addition of nut milks, many brands and varieties of dairy alternatives can be found. From almond milk to cashew milk to coconut milk, sweetened and unsweetened, blends and flavored, the choices are numerous. The choices also spill over into yogurts and dairy treats. You can even get dairy-free milk choices at your favorite specialty coffee shop. Even for those not lactose intolerant, the added choices are both tasty and nutritious.

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