Lack of vitamin B12 and folic acid increases the risk of Alzheimer’s disease, which is because these B vitamins regulate blood levels of homocysteine that must be below a certain threshold. Apparently, men and women react differently to B vitamins and folic acid with regard to cognitive functions, according to a study that is published in Nutrients. The risk of developing Alzheimer’s disease is also lower among younger people and among those who drink tea or coffee. Unfortunately, many older people lack these particular B vitamins because of poor diet habits, low stomach acid, or the use of various medical drugs.

There is a trending global shift towards vegetarian or vegan diets. However, these diets come with a risk of lacking essential nutrients that are primarily found in animal food sources. According to a large meta-analysis of Western diets, one of them is iodine. Iodine deficiency is a worldwide problem and has serious consequences because of iodine’s vital role in the thyroid function, energy production, estrogen balance, fertility, and healthy pregnancy outcome.

Hypertension and other cardiovascular diseases account for the majority of deaths. Diet and lifestyle are highly relevant, and it also appears that there is a significant linear relation between selenium intake and the risk of developing hypertension, according to a population study published in Frontiers in Immunology. The authors also mention selenium’s role in relation to blood pressure, and because selenium deficiencies are quite common, we need to look closer at this relation.

The two omega-3 fatty acids, EPA and DHA, which are found in oily fish and fish oil supplements are of vital importance to the child’s health and cognitive skills. However, according to a large American population study, 25 percent of pregnant women say that they rarely or never eat fish during their pregnancy, and even fewer take fish oil supplements. Lack of omega-3 during pregnancy can have serious consequences for the development of the child. Also, it increases the risk of postpartum depression in the mother. The study authors therefore advise pregnant women to eat oily fish or take a high-quality fish oil supplement.

Iodine is involved in the body’s production of thyroid hormones, and we humans need plenty of iodine throughout life, especially during periods such as fetal development and child development. Iodine is also important for brain development and cognitive skills. Severe iodine deficiency during pregnancy and during a child’s first years of life may result in stunted growth and/or mental retardation, but there has been uncertainty about how a minor iodine deficiency affects the child before and after birth. In a review article that is published in Nutrients, the authors look closer at iodine’s role in fertility and child growth. Apparently, iodine deficiencies are quite common, and we even need selenium and other nutrients to secure a well-functioning thyroid gland.

According to a British population study, this seems to be the case. At the same time, it’s alarming that vitamin D deficiency is such a widespread problem and that Alzheimer’s disease and other typers of dementia are on the rise, because there is most likely a connection. How does vitamin D affect brain health, and how much vitamin D do we need to help nerve cells and cells in general function optimally?

Danish scientists from Aalborg University have published a study of mice in which they demonstrate that vitamin D prevents cancer by affecting a particular kind of gut bacteria. A subsequent analysis of 1.5 million Danes shows a similar relation between low vitamin D levels in the blood and an increased risk of several cancer types. What is also worth mentioning is that the official vitamin D recommendations appear to be too low to be able optimize blood levels of the nutrient.

Vitamin D is important for our bones, mood, immune defense, blood sugar levels, for regulating inflammation, prevention of cancer, and many other functions. Most attention has been focused on vitamin D’s role in preventing brittle bones rather than its ability to prevent all the other deficiency diseases that are linked to poor well-being, disease, and early death. Vitamin D deficiency is a global problem, and science has not yet come to an agreement with regard to how much vitamin D we humans need. However, according to a new meta-analysis that is published in Nutrients, daily supplementation with 50 micrograms of vitamin D appears to be an adequate and safe dose for most adults.

Zinc has many different functions in the immune defense and a zinc deficiency increases the risk of infections and diarrhea, which are global causes of disease and mortality. According to a study published in Physiological Reports, being zinc-deficient can also lead to influenza complications such as bacterial pneumonia that is potentially lethal. The authors assume that zinc plays a key role in the body’s defense against respiratory infections, including COVID-19. They write that factors such as unhealthy diets, ageing, alcoholism, intestinal diseases, and various types of medicine can increase the body’s need for zinc.

Most people are unaware of vitamin C’s key role in mental health and mood. According to a large population study that is published in Frontiers in Nutrition, having higher levels of vitamin C in the blood is linked to a lower risk of depression. The official dietary recommendations for vitamin C only focus on preventing the potentially lethal deficiency disease called scurvy, and things like stress, ageing, stimulant use, overweight, infections, and chronic illnesses can increase your need for the nutrient.