Can reducing DHT by dietary means reduce or reverse hair loss?

Question

So, I came across this video that advertises a hair-loss prevention and reversing technique. The video is very much over the top, saying that the technique reverses hair loss in every patient, increases testosterone levels (leading to all sorts of benefits), while also preventing prostate cancer.

The term "too good to be true" has never felt more applicable, and the way it's presented doesn't make it any better - They Seem To Enjoy Capitalizing Every Word When Trying To Make Big Claims.

However, it got me wondering whether there is any grain of truth buried within the unrealistic claims made. The video is a bit tedious, so here is my summary.

This guy (if there even is a guy) claims he tried a bunch of hair growth methods, but they were expensive and had lots of side effects. Then his doctor told him he had enlarged prostate, and that this was often caused by having too much DHT (dihydrotestosterone, which he says comes from metabolizing normal testosterone) in your body.

He then goes on to say that this DHT is also linked to hair loss and that this is confirmed by a bunch of studies from Harvard and other places (no source given). He says production of DHT is controlled by an enzyme he calls 5AR (5-alpha-reductane, I believe), the production of which can be inhibited by consuming certain things (vaguely hinted as "veggies, minerals, etc... combined in specific ways"). This lets you regrow hair, lose weight, and prevents prostate cancer.

Following the instructions sold by this website is then claimed to make significant difference within four weeks. Nobody wanted to publish his results since both the hair-loss treatment and prostate cancer treatment industries are too large (this is the only part that sounds somewhat likely).

Anyway, while I (as a balding 25-year-old) wish it would be true, it all sounds like a big pile of bull feces. However, even the most exaggerated claims can contain some truth to them. So I wonder:

Is there a solid connection between hair loss and DHT (if that's even a thing)? Is there any reason to believe one could affect hair loss (and regrowth) by dietary means?

Is there something else that is blatantly wrong in the claims made in the video?

Biology and nutrition aren't my fields at all, so I don't feel like I can really answer these questions myself (or judge the credibility of sources), but here are some articles I found relating to the subject:

American Hair Loss Association

Wikipedia DHT page

Medical News Today, article on DHT

LiveStrong - "Can Foods and Vitamins Stop DHT?"

Answer 1

There are many types of hair loss (alopecia) with different symptoms and causes and alopecia may lead to permanent hair loss. "Numerous factors may be related to hair loss and range from naturally occurring processes (for example, seasonality, aging) to various biologic dysfunctions, including vitamin and mineral imbalances, endocrine disorders, immunologic diseases, and genetic mutations". Two medicines that may be effective in treating male-pattern baldness are finasteride and minoxidil. Minoxidil is currently the only medicine available to treat female-pattern baldness.

Per Finner AM in 2013, "a caloric deprivation or deficiency of several components such as proteins, minerals, essential fatty acids, and vitamins, caused by inborn errors or reduced uptake, can lead to structural abnormalities, pigmentation changes, or hair loss, although exact data is often lacking. The diagnosis for hair loss can be established through a careful history, clinical examination of hair loss activity, hair quality and confirmed through targeted laboratory tests. Examples of genetic hair disorders caused by reduced nutritional components are zinc deficiency in acrodermatitis enteropathica and copper deficiency in Menkes kinky hair syndrome."

Per Perihan Ozturk in 2014, "Copper deficiency as well as the deficiency of zinc, is known to be responsible for the etiology of hair loss and some other skin diseases, however there has been no study supporting this finding so far. Despite some positive results from patients taking the supplementation of copper, the studies on this subject are quite inadequate. Assessing the levels of trace elements in hair of male pattern androgenetic alopecia patients may be more valuable compared to serum and urine for treatment planning."

Per Urysiak-Czubatka et.al. in 2014, expert opinions about the usefulness of dihydrotestosterone (DHT) in the diagnosis of androgenetic alopecia alopecia are divided.

CONCLUSIONS: Dihydrotestosterone is the most influential androgen and seems to play a very important role in the pathogenesis of androgenetic alopecia. Based on the results of our study and others, the most important factors would appear to be the genetically-determined sensitivity of the follicles to DHT and their different reactions to androgen concentration.

Per Ralph M Trüeb in 2009, "experimental evidence supports the hypothesis that oxidative stress plays a major role in the ageing process and in contrast to topical minoxidil and oral finasteride in the management of androgenetic alopecia, topical melatonin is still being studied to represent the first topical 'antiaging' product for treatment of the ageing scalp."

Penetration and bioavailability studies (unpublished data) have so far been done in the forefront of a pilot study by Fischer et al suggesting that topically applied melatonin might influence human hair growth in vivo.

Per NHS, there is some evidence that a diet very low in iron may be linked with hair loss but in general, hair loss is unlikely to be caused by a bad diet and there’s no evidence that certain types of food boost hair growth or cause hair loss. Per Rushton DH in 2002, "excessive intakes of nutritional supplements may actually cause hair loss and are not recommended in the absence of a proven deficiency. While nutritional factors affect the hair directly, one should not forget that they also affect the skin. In the management of subjects with hair loss, eliminating scaling problems is important as is good hair care advice and the need to explain fully the hair cycle."