Nails are primarily composed of the protein keratin, so it's crucial to eat plenty of protein to keep nails healthy and strong.
The Recommended Dietary Allowance is 0.8 grams of protein per kilogram of body weight -- or 0.36 grams per pound. For a 150-pound person, that's 54 grams of protein daily.
More common in women than men, brittle nails can be from frequent hand washing stripping moisture from the nails, using acetone to remove nail polish, living in cold, dry weather, or something as simple as aging.
Thyroid disorders and iron deficiency anemia are also possibilities.
Foods rich in iron include red meat, poultry, fish, spinach, beans, whole grains and eggs.
Eyelid twitching
"Twitching in the eyelids or the limbs indicates magnesium deficiency, which is critical for transmitting nerve impulses," Sethi explained.
Myokymia is the scientific term for the orbicularis oculi, a muscle that surrounds the eye and closes the eyelids, contracting involuntarily.
The condition has been linked to stress, fatigue, caffeine consumption, an electrolyte imbalance, eye strain from staring at a computer for too long, certain medications, and less commonly, brain and nervous system disorders.
Magnesium plays a critical role in muscle function, and while magnesium supplementation is popular, experts encourage consulting with a doctor beforehand to ensure you're taking the type of magnesium that best suits your needs.
Clicking of the joints
Cracking, clicking or popping knees are a common occurrence, especially as the body ages.
However, Sethi warns "it could be a warning sign of vitamin D3 or calcium deficiency."
Premature greying of hair is when hair grays before 20 in white people and before 30 in African Americans.
Researchers don't know exactly why this happens, but they have pointed the finger at genetics, autoimmune diseases, pollution, smoking, stress and vitamin deficiencies.
"This could indicate a deficiency of vitamin B12, which is crucial for [red blood cell] production and oxygen transport at the hair follicles," Sethi said. "This could also be a sign of copper deficiency, which is responsible for melanin production, imparting color to your hair."
Bruising easily
This may be due to old age since the skin thins as the years pass; genetics, as some people are more prone to bruising easily; underlying medical conditions like Cushing syndrome or Ehlers-Danlos syndrome; medications that can reduce the blood's ability to clot, such as aspirin or blood thinners; or vitamin deficiencies.
"This could mean that you're running short of vitamin C, which is responsible for collagen formation," Sethi shared. "It could also mean a deficiency of vitamin K1, which helps in blood clotting."