Sweet Potato

Food · Vegetables · Roots, Tubers & Bulbs

Connected to · 1

food source · 1

Vitamin A
The orange in orange-fleshed sweet potato is beta-carotene, which the body converts into retinol as it needs it. It dissolves in fat, so eating it with a little fat raises absorption considerably.
Mechanism · 2
Mechanism · The orange is raw material
The orange in orange-fleshed sweet potato is beta-carotene, which the wall of the small intestine cuts and converts into retinol as needed; when the body already has enough vitamin A, this step slows, so the surplus does not keep turning into vitamin A. How much each person converts also varies. Purple-fleshed sweet potato is colored mainly by anthocyanins, and white and yellow flesh has little pigment, so none of them are sources here.
In practice · It wants oil, not dry heat
A drizzle of olive oil on steamed sweet potato, or eating it alongside a dish with some fat, helps the beta-carotene get absorbed. The cooking method also affects blood glucose: in a study of ten sweet potato varieties, boiled sweet potato had a glycemic index (GI) of about 41–50 and baked or roasted about 79–94 (Bahado-Singh 2011). For vitamin A, what counts is fat, not dry heat.

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Not a potato, not a yam

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Whether sweet potato raises blood sugar fast depends mostly on how it is cooked: the same sweet potato raises it fast when roasted and slowly when boiled — during slow roasting, more of the starch is broken down into sugar before it leaves the pan. Why roasting makes it both sweeter and faster is explained in the later chapter on how cooking decides the blood-sugar rise.

Sweet potato (Ipomoea batatas) is the swollen root of a plant in the morning-glory family. First, separate three things that often get mixed up:

It is not a potato: a potato is the swollen underground stem of a nightshade plant, a different kind of thing altogether;It is not a yam either: Chinese yam (shanyao) belongs to the Dioscorea family, and so do the yams the English word originally names; yet much of what is labeled "yam" in Western markets is actually orange-fleshed sweet potato, and the naming has always been a mess;Different flesh colors carry different pigments: orange flesh is rich in beta-carotene (which the body can turn into vitamin A), purple flesh is rich in anthocyanins, and white and yellow flesh have little pigment and lean toward starch.
Nutritionally, sweet potato combines carbohydrate with fiber, potassium, and pigments, and it is an important food crop in China and around the world. It often wears two opposite labels — weight-loss miracle and spikes blood sugar — and both need to be calibrated against the evidence.

A red-skinned, orange-fleshed sweet potato cut into two pieces. — A CLOSER LOOK
A storage root, shown in an orange variety
Sweet potatoes have different flesh colours; this orange example represents neither every variety nor its glycemic response after cooking.

Educational content, not medical advice — consult a clinician.

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