▎ WuXi AppTec content team editor
As we all know, protein, as one of the essential nutrients for human beings, plays an important role in maintaining the stability of human muscles, bones and nerves, enhancing the function of the immune system and promoting metabolism, and is the material basis of life.
According to food sources, the protein ingested by the human body can be divided into plant protein (the main source is beans, soy products, nut seeds, etc.) and animal protein (the main source is meat, eggs, milk, etc.).
Today, let's talk about the various benefits of plant protein represented by tofu for health.
Replacing animal protein with plant protein may lead to longer life
According to a study published in the Journal of the American Medical Association, compared with animal protein from foods such as red meat, if the usual intake of plant protein is higher (such as derived from tofu, etc.), it may help prolong life and reduce the risk of death.
The researchers analyzed data from the National Institutes of Health AARP Diet and Health Study, which involved 416,000 people, including 237,000 men and 179,000 women, with an average age of about 62 years.
In addition, the researchers analyzed the participants' dietary intake and source of total protein, plant protein and animal protein, and according to the nutrient density method, analyzed the protein intake per 1000 kcal of energy intake. thereinto:
Plant protein sources mainly include bread, cereals and pasta, nuts, legumes and other plant proteins;
Animal protein sources are mainly red meat (including fresh and processed red meat, mainly livestock such as pigs, cattle and sheep), white meat (such as poultry, fish and processed white meat) and other animal proteins (such as eggs and dairy products).
Image credit: 123RF
During an average of up to 16 years of follow-up, the researchers found that of the participants' total daily protein intake, 40 percent were plant-based and 60 percent were animal-based (including 19 percent dairy); the average plant-based protein intake was 26.9 g/day for men (14.4 g/1,000 kcal per day) and 21.6 g/day for women (14.9 g/1,000 kcal per day).
After further adjusting for the effects of factors such as age, sex, and alcohol consumption, the researchers' analysis found that plant protein intake was higher, which was associated with a significantly lower overall risk of death and the risk of death from cardiovascular disease.
In the case of constant total protein intake: if the proportion of plant protein is increased by 3%, while the proportion of animal protein is reduced by 3%, the overall risk of death in men and women can be reduced by 10%; the risk of cardiovascular disease death in men is reduced by 11%, and the risk of women is reduced by 12%.
Replacing 3% of total protein intake with plant-based protein by eggs reduces the risk of death by 24% for men and 21% for women, and if 3% is for red meat with plant-based protein, it reduces the risk of death for men by 13% and for women by 15%.
In addition, every 10 g/1000 kcal increase in plant protein intake in the diet reduces the risk of death by 12% for men and 14% for women – that is, the higher the proportion of plant protein in the diet, the better the longevity effect.
Researchers believe that plant-based proteins may have a variety of mechanisms for this effect.
Plant proteins contain large amounts of fiber, phenolic compounds, antioxidants, vitamins, minerals and phytoestrogens, and are high in bioactive substances that help lower systolic and diastolic blood pressure, improve lipid and lipoprotein profiles, reduce total cholesterol and LDL cholesterol (i.e., "bad cholesterol"), lower the concentration of insulin-like growth factor-1 in the blood, and promote health.
Animal proteins tend to contain higher levels of saturated fat, cholesterol, sodium, and other nutrients that are not good for health. The decomposition of animal proteins forms amino acids that can lead to hardening of the arteries or inflammation. In addition, animal protein may also affect the health of bacteria in the human gut, which in turn can endanger the overall level of health.
The researchers believe the findings support the benefits of a plant-based diet in preventing mortality from cardiovascular disease; altering the source of protein intake may affect health and longevity.
Reducing red meat from your diet is good, but only if you switch to another healthy alternative — for example, tofu instead of eggs in the morning, or beef with beans — can help prolong life and reduce the risk of death.
Eating high-quality plant protein often may prevent these 3 major types of diseases
1. Promote cardiovascular health
A recent study presented at the 2022 American Heart Association (AHA) Conference on Epidemiology, Prevention, Lifestyle, and Cardiometabolic Health also found that people who consumed the most sulfur-containing amino acids (primarily from beef, chicken, and milk) had a 12 percent increased risk of cardiovascular disease and a 28 percent increased risk of death from cardiovascular disease compared to participants who consumed the least amount of sulfur-containing amino acids.
The study authors note that this may partly explain why people who regularly eat healthy plant-based foods have lower rates of cardiovascular disease than those who regularly eat large amounts of meat and dairy products.
"In the daily diet, we should focus on healthier protein sources, and replace meat such as red meat with high-quality plant foods such as beans and soy products and nuts to promote cardiovascular health."
2. Reduce the risk of certain cancers
A growing body of research has found that eating soy and soy products not only does not increase breast cancer risk, but may also reduce the risk of certain hormone-related cancers. This may be because the soy isoflavones (a phytoestrogen) contained in soybeans can prevent the effects of the more potent estrogens.
Studies have also found that soybeans or soy products may also be associated with a reduced risk of ovarian, bladder, colorectal, liver, pancreatic, lung, head and neck cancer, etc.
In addition, studies have found that breast cancer patients who consume soy in moderation a year or more after diagnosis have the potential to improve overall survival and reduce the risk of recurrence.
3. The elderly eat more soy products to prevent dementia? Vary
In 2020, a Japanese study pointed out that whether eating more soy isoflavones can help the elderly prevent dementia may vary from person to person, depending in part on whether there are suitable bacteria in the intestine.
Because some gut bacteria convert the soy isoflavones we eat into other metabolites, the most biologically active of which is estradiol. "40 to 70 percent of Japanese people can convert soy isoflavones into estradiol, compared to only 20 to 30 percent of Americans."
The study analyzed nearly 100 cognitively normal Elderly Japanese people aged 79 to 85. Results after 6 to 9 years showed that "people with high ephedra phenol production have a smaller volume of white matter lesions in the brain, 50% less than those who do not produce ephediol." (Note: The degree of white matter lesions in the brain is an important predictor of cognitive decline and dementia.) ）
Next, the researchers plan to conduct randomized clinical trials to confirm whether equinol can protect the brain. If the results are positive, perhaps supplementing with ephedra phen may be enough for those who have difficulty converting soy isoflavones into estradiol, and for those who do not love soy products.
Beans and soy products have many benefits, see if you are suitable for eating?
Beans and soy products are not only one of the excellent sources of protein, but also a good source of dietary fiber, which has a good beneficial effect on blood lipids, postprandial blood glucose and insulin response.
At the same time, they are also rich in minerals such as calcium, vitamins, antioxidants and resistant starch, which is similar to dietary fiber and is difficult to digest and can improve satiety. At the same time, resistant starch can also improve blood sugar levels and insulin sensitivity, helping to reduce the risk of type 2 diabetes.
In addition, beans have a variety of bioactive ingredients, including folic acid and phytochemicals, that can improve cardiometabolic health.
According to the "Scientific Research Report on Dietary Guidelines for Chinese Residents (2021)" released by the Chinese Nutrition Society, the moderate consumption of soybeans and their products is related to cardiovascular disease, osteoporosis in perimenopausal women, and a reduced risk of breast cancer.
So, how much soy products are appropriate to eat?
1. For healthy adults
The Dietary Guidelines for Chinese Residents (2016) recommend a weekly intake of 210 g-350 g of soy and soy products – that is, 30 g-50 g per day.
2. For people who want to promote cardiovascular health
In 2021, a review published in Cardiovascular Research, a journal of the European Society of Cardiology (ESC), suggested that eating legumes regularly, 360-720 g per week, could be one of the dietary approaches to reduce the risk of atherosclerosis.
Another study found that consuming 400 g of legumes per week was associated with a 14 percent lower risk of coronary heart disease.
But for people with hyperuricemia and gout, whether they can eat soy products depends on the specific situation:
Northern tofu: 68 mg of purine per 100 g (because the processing process will remove a lot of water, and after boiling, the content will decrease);
Lactone tofu: 100 mg purine per 100 g;
Soybean peel: 157 mg of purine per 100 g (relatively high content due to low moisture).
Raw soy milk (5%): 7 mg of purine per 100 g, because a large amount of water is added to dilute, the purine content is lower.
In addition to looking at the content of purines, it is also necessary to consider the types of purines.
Studies have found that legumes differ greatly from the types of purines found in meat. The composition of purines in soybeans is dominated by adenine and guanine, while in the composition of purines in meat, the content of hypoxanthine and xanthine is relatively high.
In the process of metabolism, the purines in beans are more difficult to convert into uric acid, and even if the same amount of purine is ingested, the uric acid produced after metabolism is also different.
Moreover, soy isoflavones and other substances contained in soy products are also conducive to the excretion of uric acid. Therefore, there is no naming of soy products or legumes in the Dietary Guidelines for Hyperuricemia and Gout.
However, the use of soys and their products is generally recommended during the acute phase of gout attacks; in other cases, the intake of soy products is not recommended, but is not specifically restricted.