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Sweet potato

Ipomoea batatas

Also calledKumara (Māori) · Camote (Spanish, from Nahuatl camohtli) · Batata (Portuguese/Taino) · Gan shu / Fan shu (Chinese) · Satsuma-imo (Japanese) · Caiapo (white-skinned extract, Japan)

A staple root crop of the tropical Americas, the Pacific and Africa. Its main health role is nutritional: orange-fleshed varieties are rich in beta-carotene and have raised vitamin A levels in children in Africa. An extract of white-skinned sweet potato (Caiapo) has been tested for type 2 diabetes, but only in a few small trials.

Full natural-history sheet →

What it is used for

  • Eyes
    Moderate

    Vitamin A deficiency (which causes night blindness and raises child mortality): in a two-year study in rural Mozambique, promoting orange-fleshed sweet potato raised children's vitamin A intake (median 426 vs 56 µg RAE) and serum retinol. Eye outcomes were not measured directly.3,4

  • A 2013 Cochrane review found three small trials (140 people, all by one investigator) of Caiapo, white sweet potato extract: HbA1c fell by 0.3% more than placebo with 4 g/day over 3–5 months, but the evidence was judged insufficient to guide practice.1,2

  • In one of the Caiapo trials, total cholesterol at 12 weeks was lower than with placebo; not confirmed elsewhere.2

How it is prepared

food

Orange-fleshed roots boiled, steamed or mashed; carotenoid absorption improves when eaten with a little fat.

Eyes

dry extract / capsule

Caiapo, a standardised extract of the skin of white-skinned sweet potato, sold in Japan.

Trials reviewed by Cochrane (2013) used 4 g daily for up to 5 months.

Blood sugar and diabetes

Amounts are as recorded by the named source, not a recommendation.

Safety

Pregnancy
Likely safe
Breastfeeding
Likely safe
Children
Ordinary food; orange-fleshed varieties are promoted for young children's vitamin A intake.

Interactions with medicines

  • diabetes medicinesMinorCaiapo extract lowered HbA1c and glucose in trials; theoretical additive lowering of blood sugar.
Interaction checker →

Side effects

  • No serious adverse effects reported in the Caiapo trials

In the healing traditions

  • Japanese folk medicine

    Caiapo (white-skinned sweet potato)

    White-skinned sweet potato from Japan is the source of the Caiapo extract taken for diabetes; Cochrane notes sweet potato is used in traditional medicine for type 2 diabetes.

  • Modern pharmacology

    Orange-fleshed sweet potato

    Promoted in sub-Saharan Africa (Uganda, Mozambique, Kenya, Nigeria) as a food-based way to prevent vitamin A deficiency.

Active compounds

β-carotene
provitamin A carotenoid, abundant in orange-fleshed varieties
anthocyanins
in purple-fleshed varieties
chlorogenic acids
phenolic acids of the root and leaves
sporamin
main storage protein of the root

History

Sweet potato was domesticated in tropical America and reached Polynesia before European contact, where it is known as kumara. European ships carried it to Asia and Africa from the 16th century. In recent decades nutritionists have promoted orange-fleshed varieties in sub-Saharan Africa against childhood vitamin A deficiency.

Sources

  1. 1.Ooi CP, Loke SC. Sweet potato for type 2 diabetes mellitus. Cochrane Database Syst Rev 2013
  2. 2.Ludvik B et al. Efficacy of Ipomoea batatas (Caiapo) on diabetes control in type 2 diabetic subjects treated with diet. Diabetes Care 2004
  3. 3.Low JW et al. A food-based approach introducing orange-fleshed sweet potatoes increased vitamin A intake and serum retinol concentrations in young children in rural Mozambique. J Nutr 2007
  4. 4.Neela S, Fanta SW. Review on nutritional composition of orange-fleshed sweet potato and its role in management of vitamin A deficiency. Food Sci Nutr 2019

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.