What is Yogurt?
The FDA ( 1 ) defines yogurt as follows:
"yogurt is the food produced by culturing one or more of the optional dairy ingredients specified in paragraph (c) of this section with a characterizing bacterial culture that contains the lactic acid-producing bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus. ... To extend the shelf life of the food, yogurt may be heat treated after culturing is completed, to destroy viable microorganisms".
So, a yougurt must contain one or more of the following dairy ingredients as per paragraph (c): "...Cream, milk, partially skimmed milk, or skim milk, used alone or in combination".
A non-dairy yougurt is therefore not a yogurt!
It can also be heat treated, which will kill the live bacteria in it, rendering a yogurt into a non-probiotic food and therefore eliminating all the benefits provided by live microorganisms (more on this below).
The FDA also allows the addition of sweeteners (sugar, corn sirup, etc), flavoring ingredientes, color additives and stabilizers (jellies and pectins).
So a traditional yogurt delivers at least two varieties of live microorganisms: Lactobacillus and Streptococcus to your digestive tract (other live bacteria can also be added).
This dosage of microbes interacts with your gut flora (read more about your Gut Microbiome and how your diet influences it); and it is from this interaction that the health benefits of yogurt arise.
The microorganisms in your gut
Your digestive tract, and specially the intestinal mucosa -and its contents- is a dynamic ecosystem with a large variety of microorganisms (mostly bacteria, but also fungi, virus and archaea), they add up to roughly 100 trillion microbes. The live bacteria in yogurt and other probiotics (such as kefir, sauerkraut, kimchi, kefir and miso) contribute to this microbiome.
Nutrition and Dietary benefits of yogurt
Despite the lack of scientific consensus on the benefits of yogurt, there is no doubt that it helps provide essential nutrients and minerals to the diet and is also a dairy product that is suitalbe for those who suffer from lactose intolerance.
Adolfsson, Meydani & Russell (2004) ( 2 ) list these dietary and nutritional benefits as follows:
Although the Lactobacillus consume some minerals and proteins during the process of milk fermentation to produce the yogurt, especially the B Vitamins, other microbial cultures syntesize and add vitamin B to the yogurt, such as Vitamin B9 (Folic acid or Folate).
The milk protiens are "predigested" by the bacteria during frementation, producing free aminoacids such as glycine and proline, which make them more easily digestible.
Good Fat (CLA)
In regular (not the low-fat variety) yougurt, there is a higher concentration of conjugated linoleic acid (CLA) than in the milk from which the yougurt was processed. CLA is a long-chain naturally biohydrogenated molecule derived from linoleic acid (an omega-6 oil) which has some interesting properties ( 3 ):
- CLA was reported to have immunostimulatory effects
- It has a anticarcinogenic effects in animal models for stomach neoplasia, mammary tumours and skin papillomas.
- CLA may also reduce the risk of cardiovascular diseases in animal models.
- It helps lose body fat by reducing fat uptake in the body's fatty tissues.
As yougurt is acidic, it ionoizes calcium and this makes it more "bioavaliable" facilitatin its uptake in the intestines. Trials with rats show that those eating yogurt had "greater bone mineralization than did rats fed a diet containing calcium carbonate" (2). So it is far better for bone health than taking suplements.
Lactose intolerance and yogurt
The bacteria in yougurt decompose the sugar found in milk: Lactose. They decompose about 30% of the original lactose found in the yougurt mix prior to fermentation.
This meakes it better tolerated by persons with lactose intolerance.
An additional effect is that some microorganisms found in yougurt produce an enzyme called lactase which continues breaking down lactose making it even more digestible for persons with lactose intolerance.
Health Benefits of Yogurt
Several scientific studies reveal that the live bacteria found in yogurt also have heath benefits. Nevertheless the USA regulations for products containing probiotics can only state that they "support" the body or "maintain" its wellbeing. In Europe no probiotic health claims have been approved, and the word "probiotic" is not allowed on food packages. (5).
Yogurt strengthens the "good" gut microbes
Lactobacilli associate with and bind to the tissue that lines the intestine. This blocks and prevents harmful pathogens from latching on to the gut.
Yogurt Helps you to lose weight
A review of 22 publications showed a clear correlation between eating yougurt and having a lower body weight ( 10 ):
"Yogurt consumption is associated with lower body mass index, lower body weight ⁄ weight gain, smaller waist circumference and lower body fat".
Eating yougurt can help you lose weight and keep it off.
Type 2 Diabetes
Supplemetation with a multi-strain probiotic over a 6 month period helped reduce the presence of an insulin resistance marker (HOMA-IR) in patients suffering from Type 2 diabetes ( 4 ).
Although this study did not involve yogurt, the probiotic mix included included Lactococcus lactis, Bifidobacterium (B. bifidum, B. lactis), as well as Lactobacillus (L. acidophilus, L. brevis, L. casei) some of which are found in yogurts.
Some chemicals produced by the body known as proinflammatory cytokines (such as TNF-&alpha) play an important role in Crohn disease. Some studies have shown that yogurt containing Lactobacillus casei or L. bulgaricus in the presence of inflamed intestinal mucose from Chron's disease patients promoted a reduction in the release of proinflammatory TNF-&alpha, producing a beneficial effect.
More on anti-inflammatory effects below.
Yogurt has an anti-inflammatory effect
Inflammation appears to play a crucial role in several health conditions, from eczema and psoriasis to diabetes, depression and Alzheimer's disease.
According to several studies, yogurt has anti-inflammatory properties:
In one of them, ( 6 ) 120 healthy women were divided into two groups, one ate a low-fat yogurt, the other unfermented soya pudding. The calories and weight of the food was the same (12 oz., 339 g).
Blood samples were taken and analyzed during the 9-week long study.
The low-fat yougurt group showed "reduced biomarkers of chronic inflammation ... compared with a non-dairy control food", with a drop in TNF-α levels which are associated with obesity in children and adults.
The obese subjects in both groups put on almost 2 lbs (900g) body weight, but not in the case of the lean participants.
Low-Fat but with Added Sugars
The authors of the study pointed out that the yougurt despite being low-fat products (and the soya pudding) increased the sugar consumption of the participants because they included almost 2 oz. (54 g) of sugar. More on added sugars and low-fat yougurts below.
The authors, in a follow-up study ( 7 ) warned that "Therefore, consumers seeking to increase yogurt intake should be advised to maintain a healthful eating pattern."
The follow-up at the end of the 9-week study consisted of a "challenge meal" aimed at causing a metabolic dysfunction: it was a high-fat, high-carbs dish with 960 calories (hash browns, cheese sandwiches, egg and sausages). This meal was taken after the usual yogurt or soy pudding dish.
They found that those who had eaten yougurt improved their glucose response (glucose levels dropped faster). Their endotoxemia and inflammatory markers also improved.
"Premeal yogurt consumption is a feasible strategy to inhibit postprandial dysmetabolism and thus may reduce cardiometabolic risk".
"Daily consumption of yogurt may have a moderate long-term benefit in relation to metabolic endotoxemia".
The name Metabolic Endotoxemia (or ME) combines "metabolism" (how your body gets its energy from food) and "endo" (within - in this case, the body), "tox", meaning "toxins" and "emia" (in the blood). So it actually means toxins made within the body found in the bloodstream.
ME takes place after eating a "high fat" meal due to the intestinal absorption of gut lipopolysaccharides (LPS) which in turn triggers an inflamatory response in the body, with all the negative consequences provoked by inflammation.
The anti-inflammatory activity of dairy products and yogur in particular was also reported in a meta-anaysis of 52 clinical trials (Bordoni et. al., 2015) ( 8 ): "...dairy products, in particular fermented products, have anti-inflammatory properties in humans not suffering from allergy to milk, in particular in subjects with metabolic disorders".
This anti-inflammatory action is more noticeable in obese people, probably because they are already subjected to a low-grade chronic inflammation and react more readily to something that alleviates it.
But, are the regular commercial brands of yougurt beneficial?
Commercial yogurts and their health fenefits
Scourboutakos et al., (2017) ( 5 ) conducted a meta-analysis (a study which reviews data in scientific papers using sound statistical methods) and also analyzed several probiotic-containing yougurts in the Canadian market. Their study revealed that:
- Most commercial products contained only one or two different strains. Kefir products had the largest strain ⁄ species diversity of all fermented dairy products, as well as the highest count of "good" microbes: 45 billion colony forming units per serving.
- The commercial products were far less diverse than expected: only six probiotic strains were identified.
- These strains are "associated with decreased diarrhea and constipation, improved digestive symptoms, glycemic control, antioxidant status, blood lipids, oral health, and infant breastfeeding outcomes, as well as enhanced immunity and support for Helicobacter pylori eradication, but... Many studies were funded by the food industry and tested dosages that were up to twenty-five times the dosage found in most food products.
Take Home Point
So, yes, there are health benefits in commercial products, but the dosage of probiotics in yogurt is far too low for us to reap them.
Added sugars in low-fat yougurts
The fact that a yougurt is low-fat does not mean that it is healthier. In fact, the food industry adds sugar when it removes fat because lowering the fat content makes a product less tasty and more unpalatable.
A survey ( 9 ) of the sugar content in over 900 brands of yogurts in British supermarkets found that 91% of them (and 98% of children's yogurts) had more than 10 grams of sugar per every 100 gram serving. The sugar actually represented over 45% of the total energy provided by the yougurt.
The situation in the US is equally bad: the average plain low-fat yogurt has more calories than a plain whole milk one!
Below is the data for an 8 oz (227 g) container of each type of yougurt:
Plain low fat Yogurt
Plain whole milk Yogurt
The best option is a Plain, skim milk yogurt, with only 95 calories, 0.31 g of fat, 9.74 g of protein and an intermediate 13.06 g of sugar (USDA).
Watch out for fruit. They add plenty of sugar too!
Added sugars are quite a problem, you can read more abouot them in our blogpost: Sugar the poison added to our food.
Some conflicting studies: Yogurt has no effect on your health
As we have seen further up, there is plenty of evidence to support a beneficial effect of yogurt consumption on health, but not everyone agrees with this.
There are some inconsistencies in some of the studies which could be due to differences in the methodology, or the strains-dosage of bacteria used.
Below are two studies that find little or now health benefits from the consumption of yogurt:
No Health-Related Quality of Life improvements
A study by Lopez-Garcia et al., (2015) ( 11 ), followed 4,445 subjects over a period which averaged 3.5 years and found that "In comparison with people that did not eat yogurt, those who ate this dairy product regularly did not display any significant improvement in their score on the physical component of quality of life, and although there was a slight improvement mentally, this was not statistically significant".
Probiotics don't behave the same way for everyone
A recent study by Niv Zmora et al., (2018) ( 12 ) looked at the "colonization" effect of probiotic live bacteria.
The scientists analyzed stool and also took direct samples of the intestinal mucosa and found that in humans, some individuals were "permissive" while others were "resistant" when it came to allowing live bacteria in probiotics such as yogurt to colonize their intestinal mucosa.
This is a "person-, strain- and region- specific colonization resistance (in humans), the level of which significantly impacted probiotics effects on the indigenous mucosal microbiome composition, function, and host gene expression profile."
Meaning that a generalized probiotic supplement approach may not be effective for all subjects because some will benefit from them while others will just have the probiotic bacteria pass right through their gut without any of them "latching on" to the intestinal mucosa. Causing no beneficial effect.
The positive note is that a deeper understanding of the molecular basis for this permissivity and resistance, will help develop individualized probiotics that will be effective for all hosts.
Yogurt is a good way to include dairy products in your diet. This adds minerals, vitamins, protein and is a valid alternative for people who are lactose intolerant.
Yogurt (and other probiotics) appear to have different health benefits such as weight management, anti-inflammatory effects and control of diabetes type 2 among others. Though these effects may vary from one individual to another due to how each person's gut microbiome is permissive or resistant to colonization by yogurt's live microorganisms.
Finally, low-fat yogurts may not be the best option if they contain large amounts of added sugars: read the nutrition facts label for more details.
Cite this article:
A. Whittall. ©2018. Yogurt health benefits. Patagonia Wellness, 01 Jan. 2019. http://www.patagoniawellness.com/diet-food/yogurt-health-benefits.html
Subject: Yogurt's helth benefits: consuming yogurt incorporates live microorganisms into your gut and this has a positive impact on your health: weight control, anti-inflammatory effects, gut health and even management of type 2 diabetes. Learn about the beneficial role of yogurt in your diet and overall wellbeing.
References and Further Reading
(1) FDA Sec. 131.200 Yogurt. - CFR - Code of Federal Regulations Title 21. Accessed 01.01.2019
(2) Oskar Adolfsson, Simin Nikbin Meydani, Robert M Russell, (2004). Yogurt and gut function. The American Journal of Clinical Nutrition, Vol. 80:2, 1 August 2004; 245-256, https://doi.org/10.1093/ajcn/80.2.245
(3) C Kathirvelan, S Banupriya and A K Tyagi, (2015). CLA-enriched designer milk production. 17 March, 2015
(4) Shaun Sabico et al., (2018). Effects of a 6-month multi-strain probiotics supplementation in endotoxemic, inflammatory and cardiometabolic status of T2DM patients: A randomized, double-blind, placebo-controlled trial. Clinical Nutrition. Available online 17 August 2018, https://doi.org/10.1016/j.clnu.2018.08.009
(5) Mary J. Scourboutakos et al., (2017). Mismatch between Probiotic Benefits in Trials versus Food Products. Nutrients 2017, 9(4), 400; doi:10.3390/nu9040400
(6) Ruisong Pei et al., (2017). Low-fat yogurt consumption reduces biomarkers of chronic inflammation and inhibits markers of endotoxin exposure in healthy premenopausal women: a randomised controlled trial. British Journal of Nutrition Volume 118:12, 1043-1051. doi.org/10.1017/S0007114517 003038 Published online: 28 November 2017
(7) Ruisong Pei et al., (2018). Premeal Low-Fat Yogurt Consumption Reduces Postprandial Inflammation and Markers of Endotoxin Exposure in Healthy Premenopausal Women in a Randomized Controlled Trial . The Journal of Nutrition, Vol 148:6, 1 June 2018, 910-916, https://doi.org/10.1093/jn/nxy046
(8) Alessandra Bordoni, et al., (2015). Dairy products and inflammation: A review of the clinical evidence. Critical Reviews in Food Science and Nutrition Vol. 57:12; 2497-2525, 19 Aug 2015, doi.org/10.1080/10408398.2014. 967385
(9) Moore JB, Horti A, Fielding BA, (2018). Evaluation of the nutrient content of yogurts: a comprehensive survey of yogurt products in the major UK supermarkets. BMJ Open 2018;8:e021387. doi: 10.1136/bmjopen-2017-021387
(10) J Eales et al., (2016). Is consuming yoghurt associated with weight management outcomes? Results from a systematic review. International Journal of Obesity volume 40, 731-746
(11) Esther Lopez-Garcia, Luz Leon-Muñoz, Pilar Guallar-Castillon, Fernando Rodriguez-Artalejo, (2015). Habitual Yogurt Consumption and Health-Related Quality of Life: A Prospective Cohort Study. Journal of the Academy of Nutrition and Dietetics, 2015; 115 (1): 31 DOI: 10.1016/j.jand.2014.05.013
(12) Niv Zmora et al., (2018). Personalized Gut Mucosal Colonization Resistance to Empiric Probiotics Is Associated with Unique Host and Microbiome Features. Cell. 2018 Sep 6;174(6):1388-1405.e21. doi: 10.1016/j.cell.2018.08.041