Would a proper diet(etc) improve our hair quality ?

[walrus]

Sure it might be cause it's getting thinner and therefore it would be related to MPB. But isn't ther any way to make it look "better" ?

Can you not read? He specifically said the quality of hair, unrelated to MPB. They are absolutely different things. Look at someone with vitamin deficiencies, they have dull, brittle hair.

Assuming that OP does indeed suffer from MPB, are you implying that by taking vitamins his hair (that 'might be cause it's getting thinner and therefore it would be related to MPB') would improve in 'quality'?

Please define a measure of hair 'quality' that is not overridingly affected by MPB.

[hardav11]

Diet can have an effect on hair loss and changing your diet can help to slow down the rate at which you lose your hair.
The loss of the hair through MPB is inevitable though.
Autoimmune diseases such as Lupus and bacterial infections such as H Pylori can speed up the loss of your hair.
Just buy a pet mouse. They are getting all the breaks regarding haitr loss at the moment.