[Feed Knowledge] Popular Science on Selenium-Enriched Yeast

Selenium is an essential trace element for animal physiology. Currently, the primary sources of selenium supplementation in China are inorganic compounds like sodium selenite. However, these products have drawbacks such as low absorption rates and high toxicity. Adding inorganic selenium not only fails to achieve optimal supplementation results but also poses environmental pollution risks and potential harm to animals. In contrast, selenium-enriched yeast, a high-quality organic selenium source, has a higher absorption rate. After meeting the selenium needs of animals, it can also be stored in the body, preventing future selenium deficiency in the short term.

Selenium-enriched yeast is an organic selenium source developed using yeast. It is produced by accumulating selenium within the cell protein structure of growing yeast. Selenium-enriched yeast has been proven to be safer, more stable, easier to absorb, more effective, and less polluting than inorganic selenium. It also provides various health benefits. In recent years, its role in animal nutrition has gradually been recognized, and its application in livestock and aquaculture production has become increasingly widespread, showing promising effects.

Deficiency Dangers: When the blood selenium concentration falls below 85 micrograms per liter, it should be considered a selenium deficiency. The main symptoms of selenium deficiency include hair loss and nail shedding. Some patients may experience skin symptoms, while a few may develop neurological symptoms or dental damage. Mild to moderate selenium deficiency in humans often presents with subtle or non-obvious symptoms.

Selenium deficiency in the human body can cause dysfunction in major organs and lead to over 40 diseases, including energy deficiency malnutrition, hemolytic anemia, Keshan disease, osteoarthritis, hypertension, coronary heart disease, arteriosclerosis, ischemic heart disease, cardiomyopathy, leukemia, viral hepatitis, cirrhosis, pancreatitis, cancer, fibroids, myomas, diabetes, cataracts, infertility, and others.

Some estimates suggest that more than 120 million people in China may be chronic carriers of HBV (AsC), with 28 million active hepatitis B patients. The current prevalence rate is approximately 2770 per 100,000 people, with an annual incidence rate of around 230 per 100,000. Over half of China’s population has been exposed to HBV. After 16 years of investigation, medical experts discovered that the selenium levels in the blood of residents in areas with high liver cancer rates were lower than in areas with lower rates of liver cancer. There is a negative correlation between selenium levels and liver cancer incidence. Selenium supplementation can reduce the incidence of hepatitis by 35% and decrease the liver cancer incidence rate by 50% in families with a history of the disease. In China, about 1.3 million people die from malignant tumors annually, accounting for 18.63% of the country’s total annual deaths. Research shows a negative correlation between tumor incidence/mortality and selenium levels, with higher rates of tumors in low-selenium areas, and tumor patients have lower selenium levels than healthy individuals. The diabetes prevalence rate in people over 40 in China is 20.44%. The National Institute of Health and Nutrition in Japan found that selenium deficiency is one of the factors contributing to diabetes.

Clinical Applications of Selenium: The physiological effects of selenium are primarily exerted through selenoproteins, which have been shown to play roles in antioxidant activity, immune system enhancement, and thyroid hormone regulation. These effects are demonstrated in the prevention and treatment of diseases.

Slowing the Aging Process: Animal experiments show that free radicals and lipid peroxidation are major factors in membrane damage and the aging process. Lipofuscin (age spots) and waxy deposits (lipid pigments in the liver, muscles, nervous system, etc.) are indicators of aging. The body’s oxidative defense system, particularly the synergy between vitamin E and selenium, plays an important role in antioxidant activity and slowing the aging process. Although aging itself is not a disease, the body’s ability to maintain antioxidant balance declines over time, leading to oxidative damage to cells, weakened immunity, and increased susceptibility to chronic diseases. Additionally, as food intake decreases with age, dietary antioxidant intake also declines. Therefore, appropriate selenium supplementation (along with vitamin E and other antioxidants) can enhance antioxidant capacity and immunity, helping to slow the aging process in humans.

Antioxidant Action: Medical research has found that the development of many diseases is linked to reactive oxygen species (ROS) and free radicals, including cancer caused by chemicals, radiation, and smoking; myocardial oxidative damage in Keshan disease; lipid peroxidation damage in atherosclerosis; cataract formation; the aging process; and inflammation. Selenium is a necessary component of several antioxidant enzymes (e.g., GPX, TR). It helps remove lipid hydroperoxides and block the pathogenic effects of ROS and free radicals, thus preventing disease. The level of selenium in the body directly influences antioxidant capacity and resistance to related diseases.

Regulation of Thyroid Hormones: Selenium influences metabolism and related diseases through three deiodinases (D1, D2, D3), affecting conditions like iodine deficiency, Keshan disease, and aging.

Maintaining Normal Immune Function: As early as 1970, it was recognized that appropriate selenium levels are necessary to maintain both cellular and humoral immunity. The immune system uses ROS to kill invading microorganisms or toxins. For example, during infection, neutrophils produce large amounts of hydrogen peroxide (H2O2) to eliminate invading bacteria, resulting in an inflammatory response.

Controlling Virus Mutations: In 1995, Beck MA and colleagues used a benign coxsackievirus to infect selenium-deficient and selenium-sufficient mice. They then reinfected selenium-sufficient mice with myocardial extracts from the infected mice. The results showed that selenium-deficient extracts caused new tissue damage in selenium-sufficient mice. This demonstrated that selenium deficiency can lead to viral mutations, increasing virulence. This was the first report showing that selenium nutrition in the host affects viral pathogenicity. If selenium has similar effects on other RNA viruses (e.g., poliovirus, hepatitis virus, influenza virus, HIV), selenium’s impact on public health could be significant.

Prevention of Selenium-Deficiency-Related Endemic Diseases: To date, there have been no reports of purely selenium-deficient diseases in humans or animals, but many reports link selenium deficiency to conditions like Keshan disease and osteoarthritis.

Anti-Tumor Action: In 1969, American researchers Shamberger RJ and Frost DV reported a negative correlation between selenium content in crops and breast cancer mortality, as well as between soil selenium content and cancer mortality. This was one of the earliest reports linking low selenium to cancer. Subsequent studies have found similar negative correlations between human blood selenium levels and cancer mortality in different cities and between selenium intake and breast cancer mortality in different countries. In 1989, Combs GF Jr. analyzed over 100 epidemiological studies and found that two-thirds of them reported that selenium supplementation above the nutritional requirement reduced cancer incidence, with half of those studies reporting a reduction of more than 50%.

Anti-HIV/AIDS Effects: HIV/AIDS is caused by infection with the HIV-1 virus, which leads to acquired immune deficiency syndrome (AIDS). Malnutrition affects oxidative stress levels and virus expression, accelerating disease progression and death. Although experimental data are still limited, selenium supplementation for HIV-infected individuals may be an effective way to slow disease progression and improve survival rates.

Maintaining Normal Reproductive Function: Selenium deficiency can reduce sperm motility and fertility in rats, leading to deformation in the mitochondrial sheath of sperm. Severe or prolonged selenium deficiency, especially in the second generation, can halt sperm production and cause infertility.