by NATALIE VAWTER
In 1908, a Russian scientist named Elie Metchnikoff argued that people in Bulgaria were living longer and healthier lives because they were regularly eating yogurt. He believed that the bacteria living in yogurt have the power to foster healthy microbiomes, which profoundly influence people’s health. [1,2] Metchnikoff advocated daily consumption of probiotics in the form of yogurt containing lactic acid bacteria, a type of “good” bacteria.  Today, the notion that individuals can enhance their health by cultivating healthy microbiomes has escalated into a popular health craze, but it can be unclear how much truth actually exists among all the hype. To learn in depth about how probiotics and the microbiome affect your health, check out “What Are Microorganisms Doing in My Food?” (Volume 15, Issue 3). To learn about how the bacteria in yogurt confer a plethora of health benefits on yogurt-eaters, read on. People all around the world eat yogurt and make it from the milk of many mammals, from cows to camels to water buffalo. These days there are many types of yogurt to choose from, ranging from sugary choices like “Go-Gurt” to exotic options like green tea yogurt. Some kinds are healthier than others, and examining the nutrition facts can clue you into this—by choosing types with high protein levels and minimal to no added sugar, you can feel confident that your yogurt is both delicious and nutritious.
what is it?
Yogurt is essentially fermented milk. Fermentation is a process in which carbohydrates are broken down into acid or alcohol. Milk contains a type of sugar called lactose, and the lactic acid bacteria in yogurt ferment lactose to produce the lactic acid that gives yogurt its unique, tangy flavor.
Yogurt is loaded with bacterial “good guys” that populate your digestive tract to create a healthy microbiome. The most common microorganisms in yogurt are S. thermophilus, L. bulgaricus, and L. acidophilus.  These bacteria yield important health benefits, including inflammation reduction in obese people and the prevention of various types of infections.
obesity & inflammation
Obesity causes inflammation in the gut and impairment of gut bacteria, compromising the integrity of the intestinal lining and allowing harmful toxins to leak from the gut into the bloodstream.  Studies show that yogurt consumption helps reduce inflammation in the intestines by aiding immune function, strengthening the intestinal lining, and potentially keeping appetite in check.  Obesity impairs the microbiome, and eating yogurt may counteract this and therefore benefit obese individuals.
Additionally, a 2015 study published in the Cochrane Reviews found that probiotic consumption reduced upper respiratory tract infections in study participants, suggesting that regular consumption of yogurt that contains high concentrations of probiotics could reduce the number of pesky colds you get.  Yogurt also seems to prevent vaginal yeast infections in women. A 1992 study published in Annals of Internal Medicine found that women who consumed 8 ounces of yogurt daily had fewer vaginal yeast infections than women who did not, suggesting that the Lactobacillus acidophilus bacteria hinders yeast colonization.  The microbes in yogurt work hard to prevent infections, helping you to maintain better health.
lactose-intolerance no more
In addition to the health benefits discussed above, the bacteria in yogurt also help make yogurt easily digestible. Lactose-intolerant people lack the enzyme lactase and therefore cannot break down lactose, the sugar in milk. When these individuals consume milk, the lactose passes undigested into the colon where it is fermented by bacteria, resulting in diarrhea and flatulence.  However, lactose-intolerant people can consume yogurt without worrying about these unpleasant side effects. They can tolerate yogurt much better than milk, because the process of fermentation breaks down the lactose so the body doesn’t have to, making yogurt easier to digest. 
a spoonful of nutrients
Because the typical American diet is lacking in calcium and potassium, the Dietary Guidelines for Americans recommend regular consumption of dairy products such as yogurt, which contains plenty of calcium and potassium.  Importantly, the calcium in yogurt is extremely usable by the body, because the lactose and amino acids help with active transport and passive diffusion, two processes important for the absorption of nutrients.  Calcium is a crucial mineral that the body needs in order for muscles, nerves, hormones, cell signaling, and blood vessels to work properly.  Consuming a lot of calcium also keeps your bones strong! Yogurt is also a good source of B vitamins, which cells need in order to convert the energy you get from food into energy that your body can use.  Additionally, some yogurts are fortified with vitamin D, which also contributes to healthy bones.
Yogurt offers more nutrients on top of those it actually contains, since the bacteria undergo the process of fermentation and that produces additional nutrients. For example, the bacterium S. thermophilus produces folate, an important vitamin, through fermentation.  Additionally, yogurt contains conjugated linoleic acid, which may increase lean muscle mass and decrease fat mass.  All of yogurt’s beneficial nutrients come packaged with very little salt—a large bowl of yogurt contains only 1 g of salt!  Consuming too much salt can cause high blood pressure, and keeping salt consumption low can keep blood pressure stable.  Yogurt may also confer protection against certain types of cancer; a 2008 study published in the American Journal of Clinical Nutrition found that people who ate the most yogurt had the lowest levels of bladder cancer, although more studies need to be done in order to confirm these results.  Yogurt can also benefit patients with gastrointestinal problems like constipation and diarrhea.
but what about the fat?
People sometimes avoid dairy products like yogurt because they worry that the saturated fat could lead to cardiovascular disease. However, a 2009 study published in the European Journal of Nutrition showed that there is actually no association between eating dairy and developing cardiovascular disease.  On top of this, yogurt may actually aid weight loss; a recent study published in 2015 in Food, Science, & Nutrition found that overweight women were able to lose weight by consuming fewer calories and eating more protein and nonfat yogurt.  This suggests that the added yogurt in these women’s diets contributed to their weight loss success. A possible explanation for this is that high-protein yogurt may increase satiety, the feeling of fullness, and aid weight loss by suppressing appetite. By incorporating yogurt into your diet, you are setting up your body to be healthy for all these reasons.
Frozen yogurt is popular because it offers a lower fat alternative to ice cream. The microbes in yogurt can survive being frozen, so your fro yo could be benefitting your microbiome.  A downside of frozen yogurt is that it contains a high amount of carbohydrates and sugar: according to the USDA, a typical serving of one cup contains 38 g of carbs, 35 g of sugar, and 6 g of fat.  That’s a whole lot more sugar than regular yogurt! The same portion of ice cream contains 31 g of carbs, 28 g of sugar, and 15 g of fat.  Even though ice cream has more fat than frozen yogurt, frozen yogurt has considerably more sugar. Frozen yogurt should be viewed as a dessert to be eaten in moderation in order to fit into a balanced diet.
Greek yogurt is popular for a reason—it contains a ton of protein. This helps you feel more full, and is therefore effective for weight loss. The plain type is healthiest, and adding fruit, mint, and even vanilla extract can pump up the flavor without compromising the nutrition.  A cup of plain, non-fat Greek yogurt contains 23 g of protein, only 8 g of carbs, and minimal sugar. 
Made from coconut milk, this yogurt is dairy free, and therefore a good choice for people who are vegan or lactose-intolerant. One drawback of coconut yogurt is its fat content. A 6 oz container contains 6 g of saturated fat, which is 30% of the percent daily value recommended by the FDA. 
A 1998 study published in Biotechnology Progress looked at Bulgarian yogurt, which contains a type of bacteria called Lactobacillus bulgaricus, and found that these bacteria produce high levels of amino acids.  Your body takes these amino acids and uses them to build many types of proteins, from muscle cell proteins that allow you to move to antibodies that fight infections. For this reason, Bulgarian yogurt could be a particularly rich yogurt in terms of both health benefits and flavor!
icelandic yogurt (skyr)
The bacteria in Icelandic yogurt (skyr) are especially beneficial.  Skyr has a very tangy taste and thick texture, with lots of protein. It contains almost no sugar and very little fat, making it a very healthy choice. Skyr has a plain, tart taste—by adding berries, you can sweeten it up naturally.
Yogurt contains lots of good bacteria that flourish in your gut to help cultivate a healthy microbiome. This can reduce dangerous chronic inflammation in your intestines, protect against infections, and help you manage your weight by increasing your satiety.  Yogurt contains plenty of calcium, potassium, and B vitamins, and some evidence suggests that eating it regularly may ward off against certain kinds of cancer. You can use it to replace high-fat foods like mayonnaise and sour cream or as leavening in baked goods. Yogurt comes in many forms and flavors and can be a very healthy and tasty meal or snack. Whatever types are to your taste, incorporating yogurt as a regular part of your diet can bestow amazing benefits on your body!
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