Immune health: effects of dietary approaches and determinants throughout life

This thesis studied the relation between nutrition and the immune system. Compounds that were studied included plant-based nutrients with a similar structure to cholesterol and compounds formed during cholesterol synthesis in the liver. These compounds are called non-cholesterol sterols. This thesis showed that higher concentrations of non-cholesterol sterols in breast milk related to a lower risk for the child to develop eczema and allergies in the first to years of life. For eczema, this was true for 4 out of 8 non-cholesterol sterols. For allergies, this was true for 1 out of 8 non-cholesterol sterols. This thesis also showed that there is potentially a relation between cholesterol metabolism and asthma. It was also shown that consumption of plant-based nutrients with a similar structure to cholesterol increased antibody titers to the COVID-19 vaccination in people with overweight or obesity. Therefore, this high-risk group for development of severe COVID-19 complaints can potentially benefit from consuming more of these nutrients. This thesis also showed that the same nutrients did not have an effect on people with a healthy immune system. Other nutrients that were studied were certain fatty acid present in fish and certain herbs. These nutrients can potentially improve the immune system and thereby decrease complaints of asthma patients.