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Health Benefits of Yams

Reviewed by Dan Brennan, MD on September 19, 2020

Yams (Dioscorea) are often mistaken for sweet potatoes, but they are not the same vegetable. Although both grow underground as tubers, they come from differently different plants. Yams have a rough, scaly exterior which is very different from the smooth skin of a sweet potato, and are less sweet in flavor. 

Yams have a long history of being used in traditional medicine in their native areas of Asia, Africa, and the Caribbean. 

Health Benefits

May prevent and relieve arthritis symptoms

Wild yam root contains diosgenin, which has been shown to inhibit the progression of both osteoporosis arthritis and rheumatoid arthritis.

Mice who were given wild yam extract daily for 90 days showed a measurable decrease in inflammation and, at higher doses, pain levels. Human studies are still needed to determine whether these same effects would occur in humans.

May reduce cholesterol

When diosgenin extracted from wild yam root was given to mice for four weeks, it significantly reduced both their overall cholesterol levels and their LDL levels. Researchers say their results indicated that diosgenin could reduce body weight and decrease cholesterol levels. The results are promising, but human studies are needed.

May improve hormone balance

Scientists can use the diosgenin in yams to produce estrogen, progesterone, cortisone, and other hormones for medical use.

In alternative medicine, yam cream is often used in place of estrogen cream to relieve symptoms of menopause. Women are sometimes advised to eat yams to help balance their hormones, and people with hormone-related conditions are discouraged from using yams medicinally. However, studies seem to disprove this usage. The human body does not seem to be capable of converting diosgenin into hormones. More studies are needed, but it seems that using yams to treat menopause, PMS, infertility, and low libido is not effective.

Nutrition

Nutrients per Serving

Yam nutrition per 5-inch yam:

A single yam packs a whopping 369% of your daily Vitamin A requirement. Yam vitamins and minerals also include vitamin C, calcium, and iron.

Things to Watch Out For

People with hormone-connected health issues like endometriosis and uterine fibroids and anyone using estradiol-based birth control or hormone therapy should avoid yam-based medicines or large quantities of yams.

How to Prepare Yams

Most of the research on the health benefits of yams has been on specific compounds extracted from the plant root. However, if you’d like to add more yams to your diet, they are easy to prepare. 

When shopping, you may see sweet potatoes marketed as yams. To be sure you’re buying the right thing, look for a long, tapered shape and a skin that looks more like bark than potato skin. 

True yams have a very neutral flavor and tough flesh. They are best when boiled and make a nice addition to soups and stews. 

Show Sources

Sources:

Biochim Biophys Acta Mol Cell Biol Lipids: Diosgenin regulates cholesterol metabolism in hypercholesterolemic rats by inhibiting NPC1L1 and enhancing ABCG5 and ABCG8.

BMC Complementary Medicine and Therapies: Bioassay-guided evaluation of Dioscorea villosa – an acute and subchronic toxicity, antinociceptive and anti-inflammatory approach.

Bon Appetit: What's the Difference Between a Sweet Potato and a Yam?

Endocrine Reviews: Progestogens Used in Postmenopausal Hormone Therapy: Differences in Their Pharmacological Properties, Intracellular Actions, and Clinical Effects.

ESHA Research, Inc., Salem, Oregon

International Journal of Clinical and Experimental Pathology: Diosgenin inhibits IL-1β-induced expression of inflammatory mediators in human osteoarthritis chondrocytes.

Journal of Natural Products: Diarylheptanoids from Dioscorea villosa (Wild Yam)

U.S. National Library of Medicine: Wild Yam

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