Yam, raw (organic?)

The yam ( Dioscorea spp.), also called yam or yams, is a root tuber that can be prepared in a similar way to potatoes. Except for two ways, it is eaten raw inedible and rarely available in organic quality.

Use in the kitchen

The term yam is basically a collective term and includes more than 600 species of the plant genus Dioscorea. However, only a few are of importance, including the white yam ( Dioscorea rotundata), the water yam ( Dioscorea alata), the bitter yam ( Dioscorea dumetorum) and the potato yam ( Dioscorea esculenta). ¹ This article is about the yam as a genus and does not go into detail about individual species. We describe the Chinese yam ( Dioscorea batatas) in a separate article.

Externally, the yam species differ in shape, color, size and weight. The color spectrum of the flesh ranges from white to yellow to purple. The skin, however, is usually brown, rough and hairy. Depending on the type, the yam tastes sweet to slightly bitter. One often comes across comparisons with potatoes, sweet potatoes, parsnips and chestnuts - in terms of taste and consistency.

Can you eat yams raw? Yams can be boiled, cooked, baked, fried or deep-fried, but not edible raw. With the exception of a few types, the roots are toxic if eaten raw. The Chinese yam / light root, on the other hand, can be eaten raw. How can you eat yams / eat yams / eat yam? Yams can be prepared in a similar way to potatoes or sweet potatoes - rinse, peel with a vegetable peeler and, depending on the recipe, use diced, sliced or whole for casseroles, gratins, stews, soups, patties, purees or mashed potatoes (e.g. for fufu, an African porridge made from yam or cassava). Yams can also be used to make gnocchi, chips or crisps instead of potatoes. Cooked yam cubes also taste delicious in salads (e.g. particularly good with yellow bell peppers and celery) and in vegetarian or vegan curries. In general, hot sauces and exotic spices go wonderfully with yams.

The root is also used to make a gluten-free flour or powder. This can be used to make bread, pancakes, cakes and other baked goods. The purple powder of the sweet water yam (also called ube) is also used to make ube ice cream.

Vegan recipe for yam curry

Ingredients (for 3 people): 3 slices of a medium-sized yam (raw), 1 onion, 3 cloves of garlic, 1 can of cooked chickpeas, 1 can of chopped tomatoes, 150 g spinach, 2 tbsp rapeseed oil, 1 tsp garam masala, 1 tsp coriander (ground), ½ tsp ginger (ground), ½ tsp chili flakes, 500 ml water, a little salt.

Preparation: Wash the yam, peel it, cut it into slices and then dice it. Peel the onion and garlic cloves and chop finely. Heat the rapeseed oil in a pan and sauté the onion until translucent. Add the garlic and fry briefly. Add the garam masala, coriander, ginger and chili flakes. Mix in the yam pieces and rinsed chickpeas and fry briefly. Add the chopped tomatoes and water, mix well and cover and simmer for approx. 15 minutes. Remove from the heat and stir in the spinach. Season the vegan yam curry with a little salt and serve with basmati rice or flatbread, for example.

Vegan recipes with yam can be found under the note: " Recipes that have the most of this ingredient ".

Purchasing - Storage

In Europe, yams are not available in most supermarkets (e.g. Coop, Migros, Denner, Volg, Spar, Aldi, Lidl, Rewe, Edeka, Hofer, Billa). Organic supermarkets (e.g. Alnatura, Denn's Biomarkt) usually do not stock the root either. If you are lucky, you can find yams in an Asian or African grocery store or in online shops.

The availability of yams varies depending on the size of the store, catchment area, etc. Our recorded food prices for the DA-CH countries can be found above under the ingredient image - and by clicking on them you can see their development at various suppliers.

Found in the wild

Of about 50 domesticated yam species, only ten species are important as staple foods in the tropics. Most yam species are found in the wild, but these are also used as a food source in times of food shortages. ² A commonly used wild Dioscorea species is the air yam ( Dioscorea bulbifera), which occurs naturally in Asia, Africa and northern Australia. ³

Storage tips

Yam should be stored in a cool, dry place, such as in the pantry or in the vegetable compartment of the refrigerator. This way the root will last for several weeks.

Ingredients - Nutritional values - Calories

What are the nutritional values of yams? The energy content of yams (raw) is 118 kcal per 100 g. Does yam contain a large amount of carbohydrates? The majority of the calories come from carbohydrates (28 g/100g). Raw yams are low in fat with 0.17 g fat per 100 g, but also rather low in protein with 1.5 g protein per 100 g. Raw cassava (1.4 g/100g) and raw sweet potatoes (1.6 g/100g) have comparable protein contents. Raw potatoes are only slightly higher in protein with 2 g/100g. ⁴

Yams (raw) contain a significant amount of potassium. The content of 816 mg/100g (41% of the daily requirement) is comparable to that of raw chickpeas (718 mg/100g). Raw kidney beans contain a particularly high amount of potassium (1,406 mg/100g). ⁴

The vitamin B₆ (pyridoxine) content is 0.29 mg/100g (21% of the daily requirement). Potatoes (0.3 mg/100g) and wheat (0.27 mg/100g) contain a similar amount. Pistachios contain almost six times as much vitamin B₆ at 1.7 mg/100g. ⁴

100 g of raw yams also contain 17 mg of vitamin C (ascorbic acid), which makes up 21% of the daily requirement. Parsnips (17 mg/100g) and cassava (21 mg/100g) contain a similar amount. Yellow bell peppers contain significantly more vitamin C (184 mg/100g). ⁴

Yam is also rich in provitamin A (beta-carotene), from which the body can produce vitamin A. ⁵

The complete ingredients of yam root (raw), the coverage of the daily requirement and comparison values with other ingredients can be found in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.

Effects on health

Studies report on antioxidant, antimutagenic and immunomodulatory effects of yams. ³ Yams contain the steroid sapogenin diosgenin, which is used to produce steroid drugs such as cortisone or hydrocortisone. Diosgenin has antimicrobial, antifungal, immunoregulatory and anti-inflammatory effects, prevents arteriosclerosis and is said to reduce the risk of cancer. ^3,6,7,8 The hormone progesterone for hormonal treatment can be extracted from some yams. ⁵ They therefore have the potential to support the health of women during menopause. ⁹

Dangers - Intolerances - Side effects

What makes the yam root poisonous? In addition to the health-promoting substances, yams also contain substances that are responsible for the bitterness and toxicity of the raw root. These include certain alkaloids (e.g. dioscorine), phenols, oxalates, phytate, tannins and saponins. ^3,6

Mold infestation of yams is common. Mold can reduce the nutritional content of the food and produce mycotoxins that pose a health risk. ¹

Folk medicine - naturopathy

In traditional Chinese medicine ( TCM), some of the Dioscorea species are used to prevent and/or treat rheumatism, sore throats, gastropathy, cancer, and cardiovascular and cerebrovascular diseases. ^6,7

In folk medicine in some Asian and African regions, yam roots are used in a variety of ways. For example, to treat warts, wounds, gastritis, diarrhea, swelling, scorpion and snake bites, and as a soap and shampoo to kill lice. ^3,6

Ecological Footprint - Animal Welfare

Carboncloud, a Swedish climate database, calculated the CO ₂ footprint of Yam from Africa: 0.20 kg CO ₂ eq/kg. ¹⁴ This is a very small footprint, comparable to other root vegetables such as carrots or potatoes. ¹⁵

Mekonnen and Hoekstra, two leading scientists in the field of water footprint, calculated the global average water footprint of the yam. They arrived at a global average of 343 l/kg. This value is slightly above the average for vegetables, one of the most water-efficient foods, and below the average for root vegetables. ¹²

Even though the data comes from only two sources, it can be assumed that the yam is a resource-saving, climate-friendly food.

For detailed explanations of various sustainability indicators (such as ecological footprint, _CO2 footprint, water footprint), see our article: What does the ecological footprint mean?

Animal welfare - species protection

Since farmers in organic farming do not use synthetic pesticides and chemical fertilizers, organic yam is preferable for the sake of health as well as flora and fauna. ¹³

Worldwide occurrence - cultivation

The genus Dioscorea belongs to the yam family (Dioscoreaceae), the most important family within the order of the yams (Dioscoreales). It is assumed that the family is one of the earliest angiosperms (flowering plants) and has its origins in Southeast Asia. The various Dioscorea species probably followed a divergent development on the three separate continents of Africa, Asia and South America, where they were subsequently domesticated independently several times. ^2,3

The more than 600 species are widespread in the tropical, subtropical and temperate regions of Africa, Asia and South America, where they are a staple food for millions of people. ^6,7 The yam is the fourth most important tuber after potatoes, cassava and sweet potatoes. ⁶ More than 95% of the world's yam cultivation area is in sub-Saharan Africa, with Nigeria being the largest producer of yam. ¹

The only species native to Central Europe are the common painwort ( Dioscorea communis) and the Balkan painwort ( Dioscorea balcanica). ⁵

The most economically important species is the water yam ( Dioscorea alata), which originates from Myanmar and Thailand. It is highly diversified and widespread - in Southeast Asia, West Africa, South America, Central America, the South Pacific islands, etc. ³

Cultivation - Harvest

The tropical Dioscorea species grow in warm, sunny climates with temperatures between 25 ºC and 30 ºC. Short days with 10-11 hours of light lead to tuber formation, while more than 12 hours of light per day produces vine growth. Yams require loose, loamy soil that is rich in organic matter. It is best to plant the tuber plant at the beginning of the rainy season. Mulch around the plants protects them from excessive heat and drying out, especially in areas with hot temperatures and dry weather. However, yams do not tolerate waterlogging well. It is also important to train the liana-like plants up on wires and sticks so that their leaves are fully exposed to light. ¹⁰ This is the only way to achieve high yields. The yam plants take a long time to mature - some of them take a year to develop mature tubers. ¹¹

Possibility of confusion

Although the names sound very similar, the yam root is not closely related to the yam bean ( Pachyrhizus erosus).

Further information

Yams ( Dioscorea spp.) are subtropical climbing plants with mostly alternate, heart-shaped leaves and separate-sex flowers. Some of the species produce edible storage tubers in the root area, which are club-shaped to round and can weigh up to 20 kg. ⁵

Alternative names

Other common names for the yam are yams and yam. The terms Jamswurzel or Jams also appear rarely. In English, the yam is also called yam or yams.

Other uses

The cosmetics industry uses the root tuber for skin creams that are said to have cleansing and anti-aging properties. Women with menopausal symptoms or PMS (premenstrual syndrome) are also recommended to take capsules containing yam extracts (in this case it is the extract, not the hormone progesterone derived from it) - however, scientific evidence for such effects is lacking.