Yogurt, a creamy and tangy delight, has been a dietary cornerstone across various cultures, particularly in Western Asia and the Middle East. The very word “yogurt” is thought to come from the Turkish term “yoğurmak,” signifying the process of thickening, coagulating, or curdling. [1] Historically, it’s believed that nomadic herdsmen discovered yogurt by carrying milk in animal skin pouches, where natural enzymes and body heat fermented the milk into a longer-lasting, edible food compared to milk itself.
The Science Behind Yogurt
Yogurt production involves heating milk and combining it with beneficial bacteria, specifically Lactobacillus bulgaricus and Streptococcus thermophilus. This mixture then sits at a warm temperature (110-115°F) for several hours. Additional lactobacilli and bifidobacteria strains may also be included. During this process, the bacteria convert lactose, the sugar in milk, into lactic acid, which thickens the milk and gives yogurt its characteristic tart flavor.
The history of yogurt and its connection to health stretches back to 6000 BCE, as evidenced in ancient Indian Ayurvedic texts. In the early 1900s, Bulgarian microbiologist Stamen Grigorov identified Lactobacillus bulgaricus bacillus, a bacterial strain not naturally found in the human gut, as the key to yogurt fermentation. His research also explored the specific health effects of lactic acid.
Today, yogurt is available in numerous forms – from plain varieties to those with added fruits and sweeteners. Thickeners and stabilizers like gelatin and pectins are sometimes added to enhance texture and taste.
Importantly, individuals with lactose intolerance may find yogurt more tolerable than other dairy products due to its lower lactose concentration. The fermentation process breaks down lactose into lactic acid. Plant-based yogurts offer another lactose-free alternative.
Yogurt and Health: Exploring the Benefits
Yogurt provides essential nutrients, including protein and calcium. However, the primary focus on yogurt’s health benefits lies in its live bacterial content, which it shares with other fermented foods like kefir, kimchi, and sauerkraut. [2] A balanced gut microbiota is essential for overall health, and a lower diversity of some bacterial strains in the body has been linked to conditions like obesity, type 2 diabetes, irritable bowel syndrome, and chronic inflammatory diseases such as Crohn’s disease, ulcerative colitis, and rheumatoid arthritis. [3, 4]
While a plant-based diet is often associated with a diverse and healthy gut microbiota, [5] yogurt consumption can also play a role in increasing microbiota diversity. [6] You can learn more about the body’s microbiome to understand its importance.
Current epidemiological research on the specific health effects of yogurt is still evolving, but initial studies suggest positive outcomes. A study following three large cohorts for up to 20 years, involving 120,877 men and women free of obesity and chronic diseases, indicated that yogurt consumption may protect against weight gain. [7] This effect may be due to changes in gut bacteria resulting from yogurt consumption. Regular yogurt intake may also contribute to protection against heart disease and type 2 diabetes. [8,9] Two meta-analyses of prospective cohort studies demonstrated an 18% and 14% lower risk of developing type 2 diabetes with daily yogurt intake. [10,11] The exact mechanisms by which yogurt impacts diabetes are not fully understood but might involve beneficial bacteria reducing inflammation or improving insulin action.
Yogurt and Sustainability
The production of dairy foods significantly impacts land, water, and other natural resources. Dairy-producing animals, such as cattle, sheep, and goats, also produce methane, a potent greenhouse gas. The “planetary health diet” recommends a target of 250 grams of dairy foods per day (ranging from 0 to 500 grams), which is approximately one 8-ounce cup of yogurt, for a diet that’s both healthy and sustainable.
Navigating the Yogurt Aisle
When purchasing yogurt, you’ll encounter various options beyond fat content, flavor, and milk type (cow, goat, etc.). Here’s a guide to some common terms:
- Greek yogurt (strained yogurt or yogurt cheese). This type of yogurt is strained to remove whey, resulting in a thicker consistency and a distinctive sour taste.
- Plant-based or non-dairy yogurts. These yogurts, made from soy, coconut, nuts, rice, and other plant sources, are increasingly popular. Note that not all plant-based yogurts are fermented and thus may not contain live bacteria. They might also be lower in protein, calcium, and other nutrients unless fortified, so check the Nutrition Facts label.
- Probiotic. This term refers to foods, beverages, and supplements that contain specific strains of live bacteria or microbiota. Food manufacturers may add probiotics for perceived health benefits. However, the optimal amount and specific strains of bacteria for beneficial health effects can vary among individuals and are not yet fully researched.
- CFUs (colony forming units). This indicates the number of living bacteria per gram, representing the live bacteria present in the yogurt at the time of manufacture. Yogurt typically contains at least 1,000,000 (10^6) CFUs to display a “Live and Active Cultures” seal. This minimum standard accounts for bacteria that may be destroyed during digestion. While some products promote multiple bacterial strains and high CFU counts (billions), research does not consistently support these claims.
DIY Yogurt
Making strained yogurt at home is simpler than you might think:
- Heat ½ gallon of milk (skim, 2%, or whole) in a 3-quart saucepan over medium heat until small bubbles appear, stirring occasionally to prevent scorching.
- Cool the milk to 110°-115° F and transfer to a glass or ceramic bowl.
- Whisk in ½ cup plain yogurt with live cultures or a yogurt starter package. Cover the bowl and wrap it in a towel.
- Heat the oven on a warm setting for 1-2 minutes, turn on the oven light, then turn off the oven (leave the light on) and place the yogurt inside. Let it sit for at least 4 hours or overnight, maintaining an oven temperature of approximately 110°F.
- The yogurt is then ready to use. For a thinner consistency, refrigerate for a few hours before eating. For a thicker Greek-style yogurt, strain it using a fine mesh sieve lined with a coffee filter or cheesecloth and refrigerate for several hours. Store in the refrigerator for up to 7 days.
Serving Suggestions
- Opt for plain and unsweetened yogurt, either strained or unstrained. Add herbs and spices for savory dishes or fresh fruit and spices like cinnamon, nutmeg, or ginger for a sweeter treat. Top with almonds, pecans, or other nuts for added crunch.
- Create a delicious tzatziki sauce by blending 1 diced cucumber, 2-3 tablespoons lemon juice, 1 tablespoon extra virgin olive oil, 1 garlic clove, 1 tablespoon dill, and a pinch of salt and black pepper. Stir into 3 cups of plain Greek yogurt.
- Substitute plain yogurt in recipes calling for sour cream or mayonnaise. For example, use half plain yogurt and half mayonnaise in tuna salad.
Fun Facts About Yogurt
- Greek yogurt didn’t originate in Greece! The term “Greek yogurt” was popularized by a commercial yogurt company based in Greece and later adopted by other companies. Britain is the only country that regulates the term, requiring the yogurt to be produced in Greece.
- Some calcium is removed from Greek yogurt during straining. Check the Nutrition Facts label to ensure commercial Greek yogurts add back calcium.
- Some yogurts can contain up to 20-25 grams of sugar per 5 oz container. Choose lower sugar options or plain yogurt with fresh fruit and a drizzle of honey.
The Verdict: Yogurt as a Healthy Choice
Yogurt can be a valuable addition to a healthy diet. Its nutritional profile, including protein, calcium, and probiotics, offers potential benefits for gut health, weight management, and chronic disease prevention. Choosing plain, unsweetened varieties and incorporating them into a balanced dietary pattern is key to maximizing these benefits. Whether you enjoy it as a quick breakfast, a versatile ingredient in recipes, or a probiotic-rich snack, yogurt offers a tasty and potentially healthful way to nourish your body.
References
Last reviewed November 2019
