Hair has the second most prolific cell reproduction in the body and so this makes it a good barometer of changes occurring in the body. This means having a good and balanced diet can have a significant effect on your hair.
All the food you eat is eventually converted to simple compounds that the body is able to utilize - glucose being the one that supplies the energy for cell reproduction. So the most important meal of the day for the hair (and you) is breakfast. The second most important is lunch, with dinner being last.
We also said hair is a protein, therefore protein must be eaten at least for breakfast and lunch. Fresh fruit, cereal or muesli, whole wheat bread, eggs, fish, or other protein would be good for breakfast. Lean meat, fish, chicken, vegetables, baked potato, mixed salad, and more fruit for lunch or dinner. And always lots of water.
The follicle's size determines the thickness and length of the hair, and the size of the follicle is itself determined by the supply of nutrients and maintenance of high cellular energy. However, if the follicle is subjected to sebum or becomes blocked, the follicle cannot function properly and even if hair growth continues it will be at a reduced rate, quality, and thickness.
This is why regular shampooing to remove the sebum is important. Assuming you've chosen the correct products for your hair type, you cannot over shampoo. You should certainly be shampooing after exercise, or exposed to hot sunlight when sweat and sebum production will be at its worst! Also, remember to rinse thoroughly to remove all traces of product build-up.
Hair loss is normal; and with an average of up to 120,000 follicles and (potentially) hairs on your head, losing around 70 a day should not cause you any concern. However, if you start losing 70 or more a day and aren't replacing them with new hair growth, this is going to lead to a deficient hair count.
4. And finally we learned that your average head produces 44metres of hair a day, wow! (can that really be true?!)
Other factors affecting healthy hair growth include pollution, radiation, stress, and medication. Whilst for medical reasons, these causes can sometimes be unavoidable, you can still minimize the effects by following a hair program properly designed to counter the negative influence drugs, radiation, or the like, maybe having on the hair follicles' capacity to produce strong healthy growth.