This list has been compiled by Dr Patrick Kingsley - so thank you Patrick! I have added in a few of my own.

Symptoms are actually better indicators of nutritional deficiency than signs - indeed a BMJ article pointed out that 80% of diagnoses are made on the history, 6% on signs and 6% on investigations (although they didn't say how the other 8% was accounted for!) Anyhow, the following can be pointers to deficiencies, but they do not apply in all cases.

cold hands - magnesium deficiency

white spots - zinc deficiency
ridges - zinc deficiency
soft or brittle nails - magnesium deficiency
bitten nails - general mineral deficiency

stretch marks - zinc deficiency
follicular hyperkeratosis - vitamin A deficiency
spontaneous bleeds - vitamins C or K or platelet deficiency
dry scaly skin with hair follicles plugged with coiled distorted hairs and a red halo - vitamin C deficiency
yellow palms - excessive beta carotene intake
pimply rough skin at the back of the upper arms "chicken skin" - essential fatty acid deficiency

pale fissured tongue - iron deficiency
sore painful fissured tongue - vitamin B3 deficiency
sore burning tongue and lips and peeling of lips - vitamin B2 deficiency
swollen tongue with lateral teeth indentations - food intolerance
painful sore tongue with a smooth appearance - folic acid deficiency
cracked lips - vitamin B2 deficiency, thrush

pyorrhoea - Co Q 10 deficiency
bleeding gums - vitamin C deficiency

greasy red scaly skin of face and sides of nose - vitamin B2 deficiency
seborrhoeic dermatitis around nose and an acne like forehead rash - vitamin B6 deficiency

cataracts - chromium deficiency or excess free radicals
bags or dark rings under eyes - allergies or food intolerances
blue eyes and blond hair are often found in hyperactive male children - zinc magnesium, B6 and essential fatty acids deficiencies
blue eyes and premature grey hair - vitamin B12 deficiency - a feature of pernicious anaemia

thyroid swelling - iodine deficiency

any problem with the heart, including irregular beat, high blood pressure, cardiomegaly - magnesium and Co Q 10 deficiencies and sensitivity to caffeine

tender calf muscles - magnesium deficiency
brisk knee reflexes - magnesium deficiency

The following problems can suggest particular deficiencies or allergies:
Nasal polyps - salicylate sensitivity
Catarrh, sinusitis, history of removal of tonsils or adenoids - milk intolerance
Poor healing - zinc deficiency
Can't remember dreams - vitamin B6 deficiency
Sugar craving, blood sugar swings, low blood sugar - chromium deficiency, carbohydrate intolerance and gut fermentation syndrome
Pre-menstrual syndrome - magnesium, zinc and essential fatty acid deficiencies
Glandular fever - inadequate liver detoxification mechanisms
Sensory symptoms - B12, B1, magnesium deficiencies
Mental symptoms - any B vitamin deficiency! Allergies, toxic stress.
Cervical dysplasia - vitamin B6 and folic acid deficiency
Cervical papilloma/wart virus - heals well with DMSO on the end of a tampax
Arthritis - Boron and sulphur (MSM) deficiency
Measles - vitamin A deficiency
Persistent diarrhoea leading to fatigue - magnesium and potassium deficiencies
Many diuretics cause magnesium and potassium deficiencies
Muscle cramps - magnesium deficiency
Shaking hands - magnesium and vitamin B1 deficiencies
Hypertension - magnesium deficiency
Dysphagia - magnesium deficiency
Sensitivity to light - magnesium deficiency
Osteoporosis - don't forget to think about magnesium
High blood pressure in pregnancy - magnesium deficiency
Hair loss - thyroid, iron stores (must measure serum ferritin), biotin, zinc and essential fatty acid deficiencies
Frequent colds - zinc and vitamin C deficiencies
Infertility, miscarriages and premature labour - zinc deficiency
Poor sense of smell and taste - zinc deficiency
Poor vision or night blindness - zinc and vitamin A deficiencies
Dry eyes - vitamin A deficiency
The contraceptive pill and HRT can cause an increase in copper levels and zinc, magnesium and vitamin B6 deficiencies
Blocked nose with red wine - molybdenum deficiency
Any cancer or family history of cancer - selenium deficiency
Mercury amalgams in teeth - selenium and glutathione deficiencies
Cardiomyopathies (Keshan Disease) - selenium deficiency
Heart attacks - vitamin E deficiency (Shute brothers)
Hair loss, dandruff, eczema, excessive ear wax production, poor wound healing, excessive thirst (especially in hyperactive children), pre-menstrual symptoms of any sort- essential fatty acid deficiency
Carpal tunnel syndrome - vitamin B6 deficiency
Vegans - vitamin B12, zinc and Fe deficiencies
Gastrectomy - vitamin B12 and hydrochloric acid deficiencies
Diabetic peripheral neuropathy - vitamin B12 deficiency
Elderly - low everything, especially vitamin Bs and HCI deficiencies
Persistent infections vitamin C and zinc deficiencies