Here's a list of foods and the vitamins and minerals that each contains. These vitamins and minerals that are naturally occurring are a necessity to longer hair. They are:
Eggs- contain biotin, keratin, zinc, selenium, vitamin C
Berries- contain vitamin C
Spinach- contains folate, iron, vitamin C, vitamin A.
Fatty fish- examples of fatty fish are salmon, herring, mackerel. They contain omega 3 & 6, protein, selenium, vitamin D3 and B vitamins.
Sweet potatoes- contain beta carotene converts vitamin A
Avocados- contain vitamin E, neutralizes free radicals protects from oxidative stress and damage.
Nuts- contain B vitamins, zinc, essential fatty acids, vitamin E
Seeds- contain vitamin E, zinc, selenium, omega 3. Examples are sunflower, flax, and chia seeds.
Sweet peppers- contain vitamin C, and vitamin A. They contain promotes collagen, strong antioxidant, protects against oxidative stress.
Beans- contain Protein, zinc aids in hair growth, iron, biotin, and folate
Soybeans- contain spermidine that prolongs active hair growth stage; anagen phase. The longer a hair follicle stays in the anagen phase, the longer it will grow.
Meat- contains protein, iron, essential fats (This is optional based on dietary selection)