Increasing Mineral Bioavailability in a Vegan Diet

Open Access
- Author:
- Sullivan, Valerie Kristan
- Area of Honors:
- Nutritional Sciences
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dorothy Ann Blair, Thesis Supervisor
Dorothy Ann Blair, Thesis Supervisor
Gary J Fosmire, Thesis Honors Advisor - Keywords:
- vegan
mineral
bioavailability
iron
calcium
zinc
phytate
oxalate
oxalic acid
polyphenols
phytic acid - Abstract:
- A vegan diet is able to supply all nutritionally essential minerals without the use of supplements. However, the bioavailability of certain minerals may be compromised by inhibitors that are present in plants. In particular, the absorption of iron, zinc, and calcium is decreased by plant-derived inhibitors. Iron, zinc, and calcium absorption is inhibited by phytate; zinc and calcium absorption is inhibited by oxalic acid; and iron absorption is inhibited by polyphenols. If these minerals are primarily derived from poorly absorbable plant sources, an apparently “healthy” vegan diet may actually be nutritionally deficient. Reducing the concentrations of inhibitors and/or opposing their inhibitory effects can increase the bioavailability of these minerals in foods. Several food processing methods have been shown to decrease the concentration of such inhibitors. Presoaking, boiling, and draining foods is useful for reducing concentrations of phytate, oxalic acid, and polyphenols. Germination, fermentation, and bread making are additional methods that reduce phytate concentrations. The effects of inhibitors can be opposed by adding absorption-enhancing compounds to the diet. Ascorbic acid and other organic acids improve iron absorption, and citric acid may improve zinc absorption. These strategies can be used to increase the bioavailability of minerals from plants. New vegans should be taught to distinguish between sources of iron, zinc, and calcium that are well-absorbed versus those that are poorly absorbed. Presently, nutritional advice for new vegans does not fulfill this need. Therefore, an informative brochure has been developed to teach new vegans about mineral absorption inhibitors and ways to reduce their inhibitory effects and/or concentrations in foods.