Vitamin B1 (Thiamin)

100% grapefruit juice supplies thiamin, providing 8% of the Daily Value in a 250 ml serving. Smaller amounts can be found in a serving of whole grapefruit (1/2 medium) (4% DV).

  • Eat grapefruit for energy! They deliver thiamin, a water-soluble B vitamin that is associated with the action of many of the body’s enzymes and the conversion of food into energy.1,2
  • Very little thiamin is stored in the body, and because it is used up quickly, frequent consumption of thiamin from the diet is necessary.1,2


  1. Health Sheet for Professionals.Office of Dietary Supplements.National Institutes of Health.
  2. Food and Nutrition Board, Institute of Medicine.Dietary Recommended Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline.Washington, D.C.:National Academy of Sciences; 1998:58-83.