The surgery also help patients with Type-2 diabetes and obesity in controlling the condition and in treatment of cardiovascular diseases compared with people undergoing usual medical care, according to the findings.
"The striking results that we saw after metabolic surgery may be related to the patients' substantial and sustained weight loss," said the study's lead author Ali Aminian, a bariatric surgeon at Cleveland Clinic, Ohio, the USA.
"There is a growing body of evidence to suggest beneficial metabolic and hormonal changes after the surgical procedures that are independent of weight loss," Aminian said.
The study compared nearly 2,300 patients who underwent metabolic surgery with 11,500 patients with similar characteristics but under usual medical care.
Patients underwent one of the four types of weight-loss surgery -- gastric bypass, sleeve gastrectomy, adjustable gastric banding, or duodenal switch.
The primary endpoint of the study was occurrence of death due to one of the five major complications associated with obesity and diabetes -- coronary artery events, cerebrovascular issues, heart failure, atrial fibrillation and kidney disease.
Over an eight-year period, it was found that patients of metabolic surgery were 40 per cent less likely to experience one of these events than those receiving usual medical care.
Patients in the surgical group were 41 per cent less likely to die from any of these causes and had 15 per cent greater weight loss and lower blood sugar levels. They used less medication, including insulin, and less heart medications, like blood pressure and cholesterol therapies, compared with the non-surgery group.
The results were presented at the European Society of Cardiology Congress in Paris, France, and also published in the Journal of the American Medical Association (JAMA).
Isoflavones are a type of polyphenol found in legumes, including soybeans, chickpeas, fava beans, pistachios, peanuts and other fruits and nuts. Soybeans are the richest source of isoflavones, and soy foods and ingredients contain varying concentrations of isoflavones.
After eliminating a number of other factors known to increase heart risk, the researchers found that consuming tofu, which is high in isoflavones, more than once a week was associated with an 18 per cent lower risk of heart disease, compared to a 12 per cent lower risk for those who ate tofu less than once a month.
Published in the journal Circulation, the study from Harvard Medical School and Brigham and Women's Hospital analysed data from more than 200,000 people who participated in three prospective health and nutrition studies; all participants were free of cancer and heart disease when the studies began.
Read: Weight-Loss Surgery Linked To Fewer Heart Attacks, Strokes
The favourable association with eating tofu regularly was found primarily in young women before menopause or postmenopausal women who were not taking hormones.
"Despite these findings, I don't think tofu is by any means a magic bullet. Overall diet quality is still critical to consider, and tofu can be a very healthy component," said study lead author Qi Sun from Harvard University.
Soymilk, on the other hand, tends to be highly processed and is often sweetened with sugar.
The study found no significant association between soymilk consumption and lower heart disease risk.
"Other human trials and animal studies of isoflavones, tofu, and cardiovascular risk markers have also indicated positive effects, so people with an elevated risk of developing heart disease should evaluate their diets," Sun said.
"Tofu and other isoflavone-rich, plant-based foods are excellent protein sources and alternatives to animal proteins," he added.
For the study, researchers analysed health data of more than 74,000 women from the Nurses' Health Study (NHS).
The researchers emphasized that the study should be interpreted with caution because their observations found a relationship but did not prove causality.
Many other factors can influence the development of heart disease, including physical exercise, family history, and a person's lifestyle habits, they added.
Also Read: Mental Stress May Trigger A Second Heart Attack
The bacteria's activity in the intestines reduces the production of a chemical that has been linked to the development of clogged arteries, the study, published in the Journal of Biological Chemistry, said.
"The organism we studied affects health by preventing a problematic compound from becoming a worse one," said study researcher Joseph Krzycki from the Ohio State University in the US.
For the findings, the research team traced the bacteria's behaviour to a family of proteins that they suspect could explain other ways that good gut organisms can contribute to human health.
In essence, these microbes compete with bad bacteria for access to the same nutrients in the gut and if the good bacteria win, they may prevent health problems that can result from how the body metabolizes food.
Much more work is ahead, but the scientists see the potential for this microbe, 'Eubacterium limosum', to be used for therapeutic purposes in the future.
Previous research has already shown the bacterium is "good" because it calms inflammation in the gut. The chemical linked to the clogged arteries that characterise atherosclerosis is called trimethylamine, or TMA.
It is produced during metabolism when some intestinal microbes -- generally the bacteria considered unhelpful to humans -- interact with certain nutrients from food.
Among those nutrients is L-carnitine, a chemical compound found in meat and fish that is also used as a nutritional supplement to improve recovery after exercise.
The research team discovered that E. limosum interacts with L-carnitine in a different way in the gut and that interaction eliminates L-carnitine's role in the production of TMA (other nutrients also participate in TMA production in the gut).
The researchers attribute the bacteria's beneficial behaviour to a protein called MtcB, an enzyme that cuts specific molecules of compounds to help bacteria generate energy and survive. The process is called demethylation and involves the removal of one methyl group -- a carbon atom surrounded by three hydrogen atoms -- to change a compound's structure or function.
"The bacterium does this for its own benefit, but it has the downstream effect of reducing the toxicity of TMA," Krzycki said.
(IANS)
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