Vitamin deficiency is the condition of a long-term lack of a vitamin. It can be of two types:
Primary deficiency: this is when deficiency is caused by not inadequate vitamin intake
Secondary deficiency: this is when deficiency is caused by underlying disorders like malabsorption.
Some of the symptoms of vitamin deficiency include:
Mouth ulcers and cracks in the corner of the mouth: this is due to the deficiency of Vitamin B. In a small study, around 28% of patients with mouth ulcers had deficiencies in thiamine (vitamin B1), riboflavin (vitamin B2), and pyridoxine (vitamin B6).
Good sources of thiamine, riboflavin, and pyridoxine include whole grains, poultry, meat, fish, eggs, dairy, organ meats, legumes, green vegetables, starchy vegetables, nuts, and seeds.
Bleeding gums: Sometimes this can be due to rough brushing but can also be a result of vitamin C deficiency. Vitamin C plays an important role in wound healing and immunity, and it even acts as an antioxidant, helping prevent cell damage.
Taking enough fresh fruits could prevent vitamin C deficiencies.
Scurvy: this is another severe vitamin C deficiency that depresses the immune system, weakens muscles and bones, and makes people feel fatigued and lethargic.
Other common signs of vitamin C deficiency include easy bruising, slow wound healing, dry scaly skin, frequent nosebleeds. Make sure to consume enough vitamin C by eating at least 2 pieces of fruit and 3–4 portions of vegetables each day.
Vision problems: deficiency of vitamin A leads to night blindness which reduces a person’s ability to see on the dark. Vitamin A produces rhodopsin, a pigment found in the retina which helps to see at night.
Night Blindness, when untreated can lead to a condition called xerophthalmia which damages the cornea and leads to blindness.
Vitamin A is found in food such as organ meats, dairy, eggs, fish, dark leafy greens, and yellow-orange colored vegetables.
Hair loss: Lack of vitamin B3(Niacin) causes Alopecia which is a condition where the hair falls out in small patches. Lack of Vitamin B7(Biotin) also causes hair loss.
Niacin-rich foods include meat, fish, dairy, whole grains, legumes, nuts, seeds, and leafy greens. These foods are also rich in biotin, which is also found in egg yolks and organ meat.
Red or white bumps on the skin: Ketosis pilaris is a condition that causes goosebump-like bumps to appear on the cheeks, arms, thighs, or buttocks. It has been observed in people that have low Vitamin A or C in their diet. Food that contains vitamin A and C are organ meats, dairy, eggs, fish, dark leafy greens, yellow-orange colored vegetables, and fruit.
Scaly patches and dandruff: Seborrheic dermatitis (SB) and dandruff are part of the same group of skin disorders that affects the oil-producing6 areas of your body. Both involve itchy and flaky skin. The difference between them is that dandruff is restricted to the scalp and SB can appear on the face, upper chest, armpits and groin.
Low levels of niacin (vitamin B3), riboflavin (vitamin B2), and pyridoxine (vitamin B6) may each play a role.

Foods rich in niacin, riboflavin, and pyridoxine include whole grains, poultry, meat, fish, eggs, dairy, organ meats, legumes, green vegetables, starchy vegetables, nuts, and seeds.
Consumption of a balanced diet with adequate vitamin intake will keep us healthy and help us fight against diseases.