Gray hair, thin hair, hair loss... what do they warn about your health?

Stress and genes can cause your hair to turn gray.

One study found that chronic stress can actually contribute to gray hair by damaging DNA and reducing the supply of pigment-producing cells in hair follicles. Stress can also cause hair loss.

Another type of stress, called oxidative stress, can also contribute to gray hair. Oxidative stress (when free radicals damage cells and inhibit the body's repair process) can affect pigment-producing cells.

Going gray is a natural part of aging, as your hair follicles produce less color as you age. Your genes also play a role in whether your hair turns gray.

Brittle hair can be a sign ofCushing's syndrome

According to Nguyen Tri Phuong Hospital (HCMC), brittle hair is a symptom of Cushing's syndrome, a rare condition caused by too much cortisol - the body's main stress hormone. However, this is not the main symptom of the disease, there are many other more obvious symptoms of Cushing's syndrome including high blood pressure, fatigue and back pain.

Treatments for Cushing's syndrome can cause this brittle hair condition, such as glucocorticoid medications, which are steroids used to treat inflammation caused by a variety of diseases.

Thinning hair can be a sign of thyroid disease

People with hypothyroidism — a condition that occurs when your thyroid gland doesn't produce enough thyroid hormone — may notice increased hair loss and changes in hair texture.

Hypothyroidism can cause thinning hair and other symptoms, such as fatigue, cold intolerance, joint pain, muscle pain, facial swelling, and weight gain. A thyroid-stimulating hormone test can help diagnose the condition and treat it with thyroid medication.

In addition to thinning hair, some thyroid disorders put you at risk for an autoimmune hair loss condition called alopecia areata. This type of hair loss causes sudden patches of hair loss. It occurs when the immune system attacks hair follicles.

Hair loss can be a sign of anemia

If you suddenly notice more hair in your hairbrush or on the shower floor, this could be a sign that your body has low iron stores or is anemic and may need to be tested.

Blood tests are also especially recommended for vegetarians or women with heavy menstrual periods, both of which increase the risk of hair loss due to iron deficiency.

It's not entirely known why low iron levels can cause hair loss, but iron is important for many biological and chemical reactions, probably including hair growth.

If your doctor determines that you are indeed iron deficient, eating more foods high in iron or taking iron supplements may help reduce hair loss.

Hair loss can also occur temporarily due to sudden changes in estrogen levels and is often noticed after pregnancy or stopping birth control pills.

Hair loss can be a sign of protein deficiency

Protein is essential for hair health and growth, and protein deficiency has been linked to thinning and hair loss. Protein deficiency is not a problem for most people (most adults need 0.8 grams of protein per kilogram of body weight).

Good sources of protein include yogurt, lean meat, fish, eggs, and soybeans. However, most cases of thinning hair, even in women, can be genetic.

White or yellow flakes may be a sign of dandruff.

Yellow or white flakes on the hair, shoulders, and even eyebrows are signs of dandruff, a chronic scalp condition. Dandruff is usually not a sign of a serious health problem and can often be treated with shampoos specifically designed for hair.

One of the most common causes of dandruff is seborrheic dermatitis. People with seborrheic dermatitis have red, oily skin covered with flaky white or yellow scales. A yeast-like fungus called malassezia can also irritate the scalp.

Not washing your hair enough, sensitivity to hair care products, and dry skin can also cause dandruff. Dandruff is often worse in the winter, when dry weather can make skin even drier.

Damaged hair can hide other health problems

While hair can affect your health, most people complain about damage caused by coloring and using heat to style their hair.

Too much heat from daily use of a flat iron/curling iron or blow dryer can damage your hair, leaving it dry, brittle and difficult to manage. You should use no more than one hot tool per day or use hot tools infrequently.

Whenever you apply heat to your hair, always use products that have protective ingredients. Products like leave-in conditioners and shine sprays tend to protect your hair from direct and indirect heat.

Professional hair coloring is unlikely to cause much damage, but bleaching and using boxed hair dyes at home can cause side effects.

You can minimize any damage to your hair by using the right products. After coloring your hair, be sure to use a moisturizing and color-protecting shampoo that is appropriate for your hair type.