Everyone knows that amino acids are the building blocks of proteins. A sub-category, called sulfur amino acids, represented mainly by methionine and cysteine, plays various roles in metabolism and health. A plant-based diet may be the key to reducing the risk of heart disease. Penn State researchers determined that diets low in sulfur amino acids – which occur in protein-rich foods, such as meats, dairy, nuts, and soy – were associated with a reduced risk of cardiovascular disease. The team also found that the average American consumes nearly two and a half times more sulfur amino acids than the average estimated requirement. John Richie, professor of public health sciences at Penn State College of Medicine led a team that looked at the diets and blood markers of more than 11,000 participants from a national study and found that participants who ate foods containing fewer sulfur amino acids tended to decrease risk of cardiometabolic disease based on their blood test. The team evaluated data from the third national review and nutritional health survey. They compiled a composite cardiometabolic disease risk score based on the levels of certain biomarkers in the participants’ blood after a 10-16 hour fast including cholesterol, triglycerides, glucose, and insulin.
Participants were excluded from the study if they reported having congestive heart failure, heart attack, or a change in diet due to a diagnosis of heart disease. Individuals were also omitted if they reported a dietary intake of sulfur amino acids below the estimated average requirement of 15 mg / kg / day. Nutritionists collected information on the participants’ diets by making 24-hour in-person calls. Nutrient inputs were then calculated using the United States Department of Agriculture nutrient database. After taking into account body weight, the researchers found that the average intake of sulfur amino acids was almost two and a half times higher than the estimated average requirement. For decades it was understood that diets that restrict sulfur amino acids were beneficial for longevity in animals. This study provides the first epidemiological evidence that excessive intake of sulfur amino acids may be related to chronic disease outcomes in humans. These biomarkers are indicative of disease risk (eg homocysteine), as well as elevated cholesterol levels are a risk factor for cardiovascular disease. Many of these levels can be affected by a person’s longer-term eating habits leading up to the test.
Many people in the United States consume a diet rich in meat and dairy products, and the estimated average requirement should only meet the needs of half of healthy people. Therefore, it is not surprising that many are exceeding the average requirement when considering these foods that contain higher amounts of sulfur amino acids. The researchers found that higher sulfur amino acid intake was associated with a higher composite cardiometabolic risk score after accounting for potential confounding factors such as age, gender, and history of diabetes and hypertension. They also found that sulfur amino acid intake was associated with all types of food except grains, vegetables, and fruits. This indicated that sulfur amino acids alone may not be fully repositionable. Additionally, a new study has shown that fermented soy products like miso and soy sauce can help people live longer. The study was published in the latest issue of the British Medical Journal. The new study involved fifteen-year dietary data on over 92,915 Japanese men and women between the ages of 45 and 74. There were 42,750 men and 50,165 women. The eating habits and general health of these individuals were considered prior to the analysis of the results.
Consumption of fermented soy products such as miso, natto were analyzed and, on the other hand, unfermented soy products and tofu consumption were also analyzed with regards to mortality and general health. In connection with previous reports, soy is generally considered a risk in sulfur amino acids, but has not been associated with a higher cardiovascular risk. Dietary data on 138 foods and beverages were collected over five years from the participants and followed for an average of about 15 years. This was part of the prospective study based on the Japanese Public Health Center which includes 11 public health centers across Japan. The team reviewed the death certificates of participants who died during the follow-up period and looked at deaths due to cancer, heart or cardiovascular disease, cerebrovascular disease or stroke, respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD ). They divided the deaths into five categories: “cancer, mortality from total cardiovascular disease, heart disease, cerebrovascular disease, respiratory disease and injury. At the end of the follow-up, there were a total of 13,303 deaths. Participants also reported their own. smoking and other habits in the five-year survey.These were taken into account when evaluating the association between use of fermented soy products and mortality.
The results revealed that people who ate more fermented soy products like miso, soy sauce, tempeh, natto etc. They were more likely to live longer. Miso is soy that is fermented with Aspergillus oryzae. Unfermented soy products include tofu or soy curd and abura or fried tofu. These foods are commonly consumed in many Asian nations and have been found to reduce the risk of death. As a next step, the team looked at the amount needed to consume to reap the longevity benefits. Here the researchers noted that men who ate at least 50.2 grams of fermented soy products had a 10% lower risk of dying within an average of 14.8 years. This was comparable to men eating small fermented soy products. For women, the benefits of soy products could be achieved with around 48 grams of these fermented soy products each day, the researchers wrote. Natto is a traditional Japanese food in which soy is fermented with Bacilus subtilis and is a popular breakfast nationwide. This study looked at the health benefits of natto alone and found that eating 26.2 grams of natto per day reduced the risk of death by 24% in men and 21% in women.
Researchers think that the possible explanation behind the benefits of these fermented soy products could be their high fiber content. They added that these foods also contain high amounts of potassium which could be beneficial in the diet. Soy products, indeed, are rich in isoflavones and fiber which have properties to prevent the onset of cancer, heart disease, high cholesterol and weight gain. Whole soybeans are used in fermented soy products. This prevents the loss of essential nutrients, as is the case with unfermented soy products. Furthermore, fermentation of soybeans also produces bioactive compounds such as polyamines and nattokinase (present in natto). The researchers are keen to point out that the reduction in mortality risk was not observed with the consumption of total soy products. This means that consuming fermented soy products offers benefits that have not been seen with unfermented soy products. They have further studies in mind to understand exactly why these foods are linked to reducing the risk of mortality.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
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