Health Benefits of Yogurt

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Yogurt may not be the miracle food some have claimed, but it certainly has a lot to offer in the health department. Besides being an excellent source of bone-building calcium, it is believed that the bacterial cultures Lactobacillus bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus), that are used to make yogurt, carry their own health benefits.

For example, research has suggested that eating yogurt regularly helps boost the body's immune-system function, warding off colds and possibly even helping to fend off cancer. It is also thought the friendly bacteria found in many types of yogurt can help prevent and even remedy diarrhea.

For people who suffer from lactose intolerance, yogurt is often well tolerated because live yogurt cultures produce lactase, making the lactose sugar in the yogurt easier to digest (see Lactose Intolerance for advice on coping with this condition). Be sure to check the label on the yogurt carton for the National Yogurt Association's Live and Active Cultures (LAC) seal. This seal identifies products that contain a significant amount of live and active cultures. But don't look to frozen yogurt as an option; most frozen yogurt contains little of the healthful bacteria.

One research study tracked a population of 162 very elderly people for five years. The incidence of death for those subjects who ate yogurt and milk more than three times per week was 38% lower than the incidence of death those subjects who ate yogurt and other dairy foods less than once a week. (Consuming citrus fruit twice a week and a lowered consumption of meat were also associated with decreased incidence of death).

Yogurt Cuts Bladder Cancer Risk

Intakes of various foods and nutrients could influence the risk of bladder cancer, because most metabolites are excreted through the urinary bladder. With regard to dietary factors, consumption of milk and other dairy foods could potentially reduce the risk of bladder cancer.

This study aimed to examine the association between the intake of cultured milk and other dairy foods and the incidence of bladder cancer.

A statistically significant inverse association was observed for the intake of cultured milk (sour milk and yogurt). The intake of milk or cheese did not affect bladder cancer risk.

Cultured milk products contain lactic acid bacteria, which have been shown to suppress bladder carcinogenesis in rodents. The mechanism accounting for the antitumor effect of lactic acid bacteria is not clear, but it may be related to modulation of the immune system. In addition, oral administration of lactic acid bacteria has been shown to suppress food-derived urinary mutagenicity in humans, thus possibly reducing bladder carcinogenesis. The authors conclude that that a high intake of cultured milk may lower the risk of developing bladder cancer.

Lots of yogurt = low risk of diabetes

A high intake of yogurt has been found to be associated with a lower risk of developing type 2 diabetes, according to research published in open access journal BMC Medicine. This highlights the importance of having yogurt as part of a healthy diet.

Type 2 diabetes is a chronic condition that occurs when the body doesn't produce enough insulin, or the body's cells develop resistance to insulin. There is an increased risk of developing it if a relative has the condition or if an individual has an unhealthy lifestyle. Approximately 366 million people are affected by type 2 diabetes worldwide and it is estimated this will increase to 552 million people by 2030, which puts pressure on global healthcare systems.

Researchers from Harvard School of Public Health pooled the results of three prospective cohort studies that followed the medical history and lifestyle habits of health professionals. These studies were the Health Professionals' Follow-up Study (HFPS), which included 51,529 US male dentists, pharmacists, vets, osteopathic physicians and podiatrists, aged from 40 to 75 years; Nurses' Health Study (NHS), which began in 1976, and followed 121,700 female US nurses aged from 30 to 55 years; and Nurses' Health Study II (NHS II), which followed 116,671 female US nurses aged from 25 to 42 years beginning in the year 1989.

At the beginning of each cohort study, participants completed a questionnaire to gather baseline information on lifestyle and occurrence of chronic disease. Participants were then followed up every two years with a follow-up rate of more than 90 per cent. Participants were excluded if they had diabetes, cardiovascular disease or cancer at baseline. People were also excluded if they did not include any information about dairy consumption. This left a total of 41,497 participants from HPFS, 67,138 from NHS and 85,884 from NHS II.

Mu Chen, the study's lead author from Harvard School of Public Health, says: "Our study benefited from having such a large sample size, high rates of follow up and repeated assessment of dietary and lifestyle factors."

Within the three cohorts 15,156 cases of type 2 diabetes were identified during the follow-up period. The researchers found that the total dairy consumption had no association with the risk of developing type 2 diabetes. They then looked at consumption of individual dairy products, such as skimmed milk, cheese, whole milk and yogurt. When adjusting for chronic disease risk factors such as age and BMI as well as dietary factors, it was found that high consumption of yogurt was associated with a lower risk of developing type 2 diabetes.

The authors then conducted a meta-analysis, incorporating their results and other published studies, up to March 2013, that investigated the association between dairy products and type 2 diabetes. This found that consumption of one 28g serving of yogurt per day was associated with an 18 per cent lower risk of type 2 diabetes.

Previous research has suggested calcium, magnesium, or specific fatty acids present in dairy products may lower the risk of type 2 diabetes. It has been shown that probiotic bacteria found in yogurt improves fat profiles and antioxidant status in people with type 2 diabetes and the researchers suggest this could have a risk-lowering effect in developing the condition. To confirm this observation, and investigate whether or not yogurt is causal in the lowering of risk, randomized controlled trials are needed.

Senior researcher on the study Frank Hu, Harvard School of Public Health, says: "We found that higher intake of yogurt is associated with a reduced risk of type 2 diabetes, whereas other dairy foods and consumption of total dairy did not show this association. The consistent findings for yogurt suggest that it can be incorporated into a healthy dietary pattern."

Yogurt consumption reduces the risk of type 2 diabetes

New research published in Diabetologia (the journal of the European Association for the Study of Diabetes) shows that higher consumption of yoghurt, compared with no consumption, can reduce the risk of new-onset type 2 diabetes by 28%. Scientists at the University of Cambridge found that in fact higher consumption of low-fat fermented dairy products, which include all yoghurt varieties and some low-fat cheeses, also reduced the relative risk of diabetes by 24% overall.

Lead scientist Dr Nita Forouhi, from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge, commented "this research highlights that specific foods may have an important role in the prevention of type 2 diabetes and are relevant for public health messages".

Dairy products are an important source of high quality protein, vitamins and minerals. However, they are also a source of saturated fat, which dietary guidelines currently advise people not to consume in high quantities, instead recommending they replace these with lower fat options.

Previous studies on links between dairy product consumption (high fat or low fat) and diabetes had inconclusive findings. Thus, the nature of the association between dairy product intake and type 2 diabetes remains unclear, prompting the authors to carry out this new investigation, using much more detailed assessment of dairy product consumption than was done in past research.

The research was based on the large EPIC-Norfolk study which includes more than 25,000 men and women living in Norfolk, UK. It compared a detailed daily record of all the food and drink consumed over a week at the time of study entry among 753 people who developed new-onset type 2 diabetes over 11 years of follow-up with 3,502 randomly selected study participants. This allowed the researchers to examine the risk of diabetes in relation to the consumption of total dairy products and also types of individual dairy products.

The consumption of total dairy, total high-fat dairy or total low-fat dairy was not associated with new-onset diabetes once important factors like healthier lifestyles, education, obesity levels, other eating habits and total calorie intake were taken into account. Total milk and cheese intakes were also not associated with diabetes risk. In contrast, those with the highest consumption of low-fat fermented dairy products (such as yoghurt, fromage frais and low-fat cottage cheese) were 24% less likely to develop type 2 diabetes over the 11 years, compared with non-consumers.

When examined separately from the other low-fat fermented dairy products, yoghurt, which makes up more than 85% of these products, was associated with a 28% reduced risk of developing diabetes. This risk reduction was observed among individuals who consumed an average of four and a half standard 125g pots of yoghurt per week. The same applies to other low-fat fermented dairy products such as low-fat unripened cheeses including fromage frais and low-fat cottage cheese. A further finding was that consuming yoghurt in place of a portion of other snacks such as crisps also reduced the risk of developing type 2 diabetes.

While this type of study cannot prove that eating dairy products causes the reduced diabetes risk, dairy products do contain beneficial constituents such as vitamin D, calcium and magnesium. In addition, fermented dairy products may exert beneficial effects against diabetes through probiotic bacteria and a special form of vitamin K (part of the menaquinone family) associated with fermentation.

The authors acknowledge the limitations of dietary research which relies on asking people what they eat and not accounting for change in diets over time, but their study was large with long follow-up, and had detailed assessment of people's diets that was collected in real-time as people consumed the foods, rather than relying on past memory. The authors conclude that their study therefore helps to provide robust evidence that consumption of low-fat fermented dairy products, largely driven by yoghurt intake, is associated with a decreased risk of developing future type 2 diabetes.

Dr Forouhi stated that "at a time when we have a lot of other evidence that consuming high amounts of certain foods, such as added sugars and sugary drinks, is bad for our health, it is very reassuring to have messages about other foods like yoghurt and low-fat fermented dairy products, that could be good for our health".