It is generally agreed today that obesity is a risk factor for multiple health problems, but its association with androgenetic alopecia remains controversial. I often notice that overweight people usually show signs of diffuse hair loss. Although excessive eating is not the direct cause of baldness, they can be linked in some way.
Recent studies showed that higher body mass index (the official indicator used to define the degree of obesity) is significantly related to greater severity of hair loss in men with androgenetic alopecia. Obesity is a key feature of metabolic syndrome and is associated with multiple endocrinologic, metabolic, and hormonal changes. Possible explanations for the link between male pattern baldness and obesity may include the presence of insulin resistance and up-regulation of insulin-like growth factor-1 in people with excessive weight. Insulin and IGF-1 are closely related peptide hormones that may induce 5α-reductase activity, leading to an increased conversion of testosterone to dihydrotestosterone, which is responsible for male pattern baldness.
Other evidence suggests that enlarged fat cells influence the physiology of the folliculosebaceous unit. For example, hirsutism, the excessive hairiness in those parts of the body where hair is typically fine, is significantly correlated with body mass index independent of age and testosterone level in adults. It is known that conversion of fine vellus hair to thicker terminal hair occurs because of androgen-mediated signals on the face, axilla, and chest, whereas these same androgen signals lead to miniaturization of the scalp hair. However, the fate of the hair follicle may also be determined by site-specific factors. For example, excessive hair growth can be caused by nonandrogen inflammatory cytokines after trauma or in response to proliferative epidermal and vascular growth factor similar to those associated with obesity. Moreover, factors derived from the adipose tissue (such as bone morphogenetic protein-2, leptin, and adiponectin) can be determinant for hair growth and cycling.
The last idea that I am going to mention is very easy to come up with. It is a well-known fact that overweight people tend to lead a sedentary lifestyle that affects peripheral circulation of blood, and this means that hair follicles will be poorly nourished.
Nevertheless, many questions remain open, such as whether reduction of body weight benefits the treatment of alopecia. Due to the complex interaction between genetic, hormonal, and metabolic factors, the effect of obesity on hair growth still needs to be carefully studied. As for me, healthy diet makes me feel good and gives me tone to fight against aging. It was also shown that calorie restriction deactivates mTOR and increases life span. All in all, I would like to conclude with a proverb – measure is a treasure.