Role of vitamins in gastrointestinal diseases

Table 1 Major characteristics of the known vitamins

Vitamin	Recommended daily doses1	Major dietary sources	Deficiency syndromes	Tolerable daily upper intake levels
A	M: 900 μg	Orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, liver, soy milk, milk, sweet potatoes, butter, egg yolk	Night-blindness	3000 mcg
(Retinol, Carotenoids)	F: 700 μg		Hyperkeratosis, keratomalacia
B1 (Thiamine)	M: 1.2 mg	Whole grains, dried beans, oatmeal, brown rice, potatoes, pork, liver	Beriberi - dry (peripheral neuropathy) or wet (heart failure), Wernicke encephalopathy	ND
	F: 1.1 mg
B2 (Riboflavin)	M: 1.3 mg	Dairy products, bananas, popcorn, green beans, asparagus, dark green leafy vegetables	Rare	ND
	F: 1.1 mg		Non-specific symptoms
B3 (Niacin, Nicotinic acid)	M: 16.0 mg	Meat, fish, eggs, mushrooms, tree nuts, peas, bran	Pellagra	35 mg
	F: 14.0 mg
B5 (Pantothenic acid)	5.0 mg	Fortified cereals, Salmon, Meat, broccoli, avocados	Paresthesia, “burning feet”, GI symptoms	ND
B6 (Pyridoxine)	1.3-1.7 mg	Meat, liver, tree nuts, bananas, salmon, tuna, brown rice, potatoes	Anemia, peripheral neuropathy, insomnia, seborrheic dermatitis, stomatitis	100 mg
B7 (Biotin)	30.0 μg	Raw egg yolk, liver, peanuts, certain vegetables	Dermatitis, enteritis	ND
B9 (Folic acid)	400 μg	Spinach, enriched rice, fortified cereal, liver, avocado, lentils	Megaloblastic anemia	1000 mcg
			Neural tube defects
B12 (Cobolamine)	2.4 μg	Meat, salmon, egg yolk, lentils, spinach	Megaloblastic/Pernicious anemia	ND
C (Ascorbic acid)	M: 90 mg	Citric fruits, papaya, broccoli, strawberries, paprika, liver	Scurvy	2000 mg
	F: 75 mg
D (Cholecalciferol, Ergocalciferol)	15 μg	liver, mushrooms, fatty fish, milk, egg yolk, fortified cereals	Rickets and osteomalacia	100 mcg (4000 IU)
	(> 70 yr: 20 μg)	1 cup of milk = 50 IU; 30 min of sunlight = 10000 IU
E (Tocopherols)	15.0 mg	Sunflower seeds, almonds, fortified cereals, spinach, turnip greens	Very rare; mild hemolytic anemia, ataxia, neural degeneration	1000 mg
K (phylloquinone, menaquinones)	M: 120 μg	Leafy green vegetables, egg yolks, liver, mustard greens, asparagus, kiwi, dried prunes	Bleeding diathesis	ND
	F: 90 μg

¹In adults, not pregnant nor lactating. ND: Not determinable.