12/08/2025
Many female patients seek help from natural therapists for hair loss precisely because conventional medicine has so little to offer beyond diagnosis and reassurance. Once serious pathology (like thyroid disease or marked iron deficiency) is ruled out, women are often told their hair loss is “normal” with age or hormonal change — and offered little more than topical minoxidil, oral contraceptives or anti-androgen medications. These treatments can help in some cases, but many women find them partially effective, poorly tolerated or unsatisfying. Also, many men suffer from poor hair health not necessarily related to male pattern baldness.
There are many retail supplement products aimed to help with hair health, but what is the evidence for their efficacy. And does diet play a role?
While a growing body of evidence highlights the roles of genetics and hormones in alopecia and general hair follicle health, emerging evidence suggests the profound influence of diet and nutrition in optimal hair outcomes.
In a recent study in the journal Nutrition and Health, researchers synthesised evidence from 17 peer-reviewed publications, collectively leveraging more than 61,332 participants, to unravel the science on dietary impacts on hair health.
Review findings highlight that vitamin D concentrations demonstrated a strong inverse correlation with alopecia (hair loss) severity, providing an example of the importance of specific micronutrients in optimal hair health (although one large cohort study found no association). Conversely, the high consumption of sugary drinks (>3500 mL/week) was positively correlated with hair loss, particularly in men.
The included studies comprised cross-sectional studies (n = 7), case-control studies (n = 4), three randomised clinical trials, two clinical trials, and one cohort study. The reviewed studies covered more than 61,332 participants, though this number was heavily and disproportionately populated by one extensive cohort study. Most of these participants were female (97%), with summary statistics revealing that vitamin D was the most frequent topic of investigation among included studies (n =5).
The outcomes of these investigations were generally consistent – lower serum vitamin D levels were associated with greater severity of both alopecia areata (an autoimmune form of hair loss) and androgenetic alopecia (pattern baldness), though the null finding in one cohort highlights that evidence is not uniform.
In contrast, a Japanese case-control study found that a high intake of retinol (vitamin A) was associated with a greater severity of alopecia areata, suggesting a complex, non-linear relationship for some nutrients and highlighting the importance of dosage in achieving optimal hair health.
Finally, a cross-sectional study in China of 155 women with feminine alopecia highlighted the benefits of dietary iron, finding that iron supplementation was associated with improved hair growth.
The systematic review also cautioned against the impacts of specific suboptimal dietary and lifestyle choices (alcohol consumption or sugary beverages). For example, as already noted, a cross-sectional study of 1,028 young men in China found that excessive consumption of sugary drinks (>3500 ml/week) substantially increased hair loss. In another study, alcohol consumption was associated with both increased hair loss and premature hair depigmentation.
Other nutrients and foods were also highlighted: a 1971 clinical trial linked protein deprivation to reduced hair bulb diameter and pigmentation, while one cross-sectional study found that higher intakes of cruciferous vegetables and soy products were associated with reduced hair loss, though the soy finding was not statistically significant. Several randomised clinical trials of supplements (marine protein complex, eggshell membrane, persimmon leaf extract) showed improvements in hair density, gloss, or reduced loss, but many carried a high risk of bias, limiting the strength of these conclusions.
For more information see: https://www.news-medical.net/news/20250825/Sugary-drinks-increase-hair-loss-risk-scientists-warn.aspx
