1. Dietary deficiencies rarely occur in isolation; if you're deficient in one nutrient, you're likely to be deficient in another. For example, a diet low in protein is also often low in iron, zinc, thiamin and vitamin B₆. Under typical circumstances it is very difficult to choose a diet based on whole foods that is deficient in a single nutrient.

2. A definitive diagnosis is very rarely made based on observation of a single symptom. Many different nutrient deficiencies cause similar symptoms. For instance, deficiencies of B₁, B₆, and potassium are all associated with mental confusion, as is lead toxicity; but these are not the only causes of mental confusion. Lack of sleep, drug use, brain injury, and organic brain disease would all need to be ruled out before you could point to a deficiency or excess of any one nutrient.

3. Isolated symptoms of toxicity have become more common than are isolated symptoms of nutrient deficiency. This is due to the widespread availability and use of supplements, many of which are rich in a single nutrient.

It is very important to keep these points in mind when reviewing the following chart. This chart can provide you with clues for recognizing problems in your own diet, but it should not replace a visit to your doctor if your symptoms are severe.

TISSUE/ORGAN	SYMPTOM	POSSIBLE NUTRITIONAL DEFICIENCY OR TOXICITY
Hair (on head)	Depigmentation of hair	Protein deficiency
	Flag sign: Stripes of depigmented hair	Transient, reoccurring protein deficiency
	Hair loss	Biotin deficiency; vitamin A toxicity
	Dry, Brittle hair	Iodine deficiency
Hair (body)	Profuse, long body hair (lanugo)	Anorexia
Eyes	Night blindness	Vitamin A or zinc deficiency
	Xeropthalmia	Advanced vitamin A deficiency
	Macular degeneration	Age + lack of xantheine, an antioxidant from the carotene family commonly found in pumpkin, summer squash, and dark green vegetables.
	Retinal degeneration	Excess blood sugar (common in poorly regulated diabetes)
	Dark under-eye circles	May indicate iron deficiency
	Yellow "whites"	Jaundice from liver disease; excessive beta-carotene intake
Mouth	Bleeding gums	Vitamin C deficiency
	Loose teeth	Advanced vitamin C deficiency (scurvy)
	Cracked lips + swollen, dark red tongue	Riboflavin (Vit B2) deficiency
	Swollen dark red tongue	Biotin deficiency
Throat	Goiter	Iiodine deficiency; autoimmune induced loss of thyroid function (hypothyroiditis)
Cardiovascular	Hypertension	Excess sodium; lack of calcium & potassium; excess body weight & poor physical conditioning; also genetic causes
	Atherosclerosis (blocked circulation)	High fat (especially saturated) diet often accompanied by obesity
	Poor circulation	Capillary damage due to poorly regulated diabetes
	Heart attack	See atherosclerosis; potassium deficiency or toxicity are also remote possibilities
	Stroke	See hypertension, atherosclerosis
Respiratory	Asthma	A genetically increased requirement for vitamins E & C; may accompany food allergies; exacerbated by sulfites (food preservatives)
	Cancer	Possible deficiency of antioxidants & phytochemicals found in produce; exposure to environmental toxins, including those found in some foods; genetic component with some cancers, e.g. colon and ovarian
Liver	Failure	Alcohol toxicity; poisonous foods & herbs, e.g. some mushrooms; excess use of supplements such as vitamins A, D, B6, and niacin
	Fatty	Early stages of alcoholism
	Gallstones	High fat diet + obesity, especially in overweight women of reproductive age
Kidneys	Damage	Exposure to environmental toxins, including those in some foods; excess nutrients such as fluoride
	Failure	Hyperglycemia due to poorly regulated diabetes; high protein diets
	Stones	Excess calcium
Pancreas	Pancreatitis	Alcoholism
	Autoimmune damage (insulin dependent diabetes)	Elevated blood glucose
	Cystic fibrosis	Nutrient deficiencies due to lack of digestive enzymes
Gastrointestinal tract	Constipation	Lack of dietary fiber
	Colon cancer	Lack of dietary fiber; antioxidant deficiency; genetic predisposition
	Diarrhea	Deficiency of nutrients used to build intestinal lining, including protein, zinc, vitamin A, and B-complex vitamins
Urogenital tract	Recurrent bladder infections	May indicate lack of sufficient nutrients to build up a good lining
	Excess urination	Microbial infection; diabetes; excess caffeine consumption
	Insufficient urination	Dehydration
	Unusually colored urine	Illness; excess intake of supplements such as vitamin C, riboflavin or carotinoid antioxidants
	Prostate cancer	Insufficient intake of the antioxidant luetein (the red pigment in tomatoes)
	Hypogonadism	Zinc deficiency in childhood
Skeleton	Bowed legs, protruding breastbone (rickets)	Vitamin D deficiency during childhood
	Frequent fractures (osteomalacia)	Loss of calcium from bones due to adult vitamin D deficiency
	Pre-osteoporosis (osteopenia)	Weakened bones caused by lack of calcium during teen and adult years
	Osteoporosis	Brittle calcium-deficient bones caused by poor diet and age-related hormone changes
	Hypercalcification	Vitamin A toxicity
	Stunted growth	Starvation, protein deficiency
	Dwarfism	Possible zinc deficiency
Skin	Pellegra (dry, black skin)	Niacin (vitamin B3) deficiency
	Dry, scaly skin	Essential fatty acid, vitamin E, or biotin deficiency
	Greasy, scaly	Riboflavin (B2) deficiency
	Dry, stays peaked when pinched	Dehydration (water deficiency or electrolyte imbalance)
	Unusual skin rash	Excess supplement use; vitamin B6 deficiency
Soft tissues	Wasting	Anorexia nervosa; involuntary starvation; thiamin deficiency
	Delayed wound healing	Vitamins C, A or zinc deficiency
	Calcification	Vitamin D toxicity
Neurological system	Numbness in extremities	Vitamin B6 toxicity; vitamin B1 deficiency (Beriberi)
	Persistent tremors	Alcoholism
	Mental confusion	Starvation; deficiency of vitamin B6 or B1 (Beriberi), iron, and potassium; profound niacin deficiency; lead toxicity; must rule out brain injury or disease
Red Blood Cell Indexes (Anemias)	Hemolytic anemia	Vitamin E deficiency
	Hemorraghic anemia	Vitamin K deficiency
	Macrocytic anemia	Folate deficiency
	Microcytic anemia	Iron deficiency; zinc or vitamin B6 deficiency
	Pernicious anemia	Vitamin B12 deficiency; dietary or genetic causes
	Lack of clot formation	Vitamin K deficiency; vitamin E toxicity
Blood Chemistry	Hyperglycemia (diabetes)	Elevated blood glucose
	Poor glucose clearance	Noninsulin dependent diabetes: chromium deficiency; excess body weight; genetics
	Hypoglycemia	Low blood glucose; a symptom, not a disease. Two types: reactive, which is caused by skipping meals or starvation, and spontaneous, which is caused by over-production of insulin following a meal; may indicate a pancreatic tumor.
	Hypercholestremia	High fat diet + obesity; genetics
	Hyperlipidemia	High fat diet + obesity; genetics
	Electrolyte imbalances	Dehydration due to disease, heat exhaustion, overexertion, insufficient fluid intake, or excess use of diuretics, emetics or laxatives
	Anemias	See Red Blood Cell Indexes