Yoruba Have A High Twin Birthrate Because Of Their Yam Consumption?

The yam is a common vegetable for the majority of us, often served in a deep orange dish at our holiday tables. However, as our most recent contributor explains, this tuber’s meat, which can be found in a variety of colors from white to violet, is actually a highly prized and ancient source of food with significant cultural significance.

In four continents, the yam thrives in humid, tropical environments, including Africa. In fact, the starchy tuber is an essential staple food in West Africa, providing more than 150 million people with over 200 calories per day. It is available throughout the year and can be prepared in a variety of ways. For the sake of food security, some varieties can even be stored for up to six months.

Source of Income

Additionally, it provides farmers with limited resources with an essential source of income. It is planted in dirt mounds or ridges, and in order to harvest the tuber without damaging it, workers must carefully dig into the soil mounds. Over 95% of the world’s yam crop is harvested in West Africa, where Nigeria is the largest producer, despite these difficult conditions. It is not surprising that there are a lot of yam festivals in Nigeria, when people celebrate and give thanks.

Yoruba to New Orleans

Additionally, yams offer a culinary connection to history. In “From Yoruba to New Orleans:,” his essay, The Divine Yam,” written by Kiel Adrian Scott, delves into the many roles yams have played throughout history, from the phenomenon of multiple births in Nigeria to the connection between Kiel and his cultural identity to providing a taste of home for those relocated to a new land. The yam is typically boiled, fried, or roasted in most dishes, but Kiel and his twin brother prefer to eat it in a baked pie.

Sweet Potatoes And Twin Pregnancy Connection

There are many theories, and you can explore some of them here. The most interesting theory, to us at least, is the Sweet Potato theory. I first heard of this theory from a friend who had her first set of twins in her second pregnancy.

I have no way of knowing if this idea is true, but there is some evidence that eating large amounts of yams or sweet potatoes increases your chances of having fraternal twins. There is a tribe in Africa, the Yoruba, who have the highest rate of twins in the world. Interestingly, they eat many sweet potatoes. In fact, it is a staple of their diet, so most of what they eat is sweet potatoes.

“Yorubas have the world’s highest twin birthrate because of their high yam consumption rate. Eating yam increases the chances of having twins.”

A picture says it all

Sights like this can be seen everywhere in Igbo Ora, where a banner welcomes visitors to the “twins capital of the world”.

Twins are common in the Yoruba ethnic group that dominates this part of Nigeria. A 1970s study by a British gynaecologist found that around 50 sets of twins were born out of every 1,000 births in the southwest – one of the highest rates of twin births in the world.

In Yoruba culture twins are so common that they are traditionally given specific names. They are called either Taiwo or Kehinde depending on whether they were born first or second.

Is there any data to back up these claims?

Lagos-based gynaecologist and obstetrician, Prof Oladapo Ashiru says that the yam claim is common and that twin birth rates are particularly high in the Nigerian town called Igbo-Ora in Oyo state.

The town which is about 142 km north of Lagos, has previously been dubbed “the land of twins”.

It has been widely reported that community members believe that the prevalence of twins in their society is largely due to the food they eat. More specifically, they believe that their high consumption of yam is the reason for the significant rate of twinning in Igbo-Ora.

• Yams are tuber vegetables like potatoes, Ashiru explained. The crop is grown in many parts of west and central Africa.

A 2008 study noted that yams are believed “to contain a natural hormone phytoestrogen, which may stimulate multiple ovulation”.

• One theory is that yams prompt the production of gonadotropins, a chemical agent that stimulates the production of eggs.

But the idea that eating yam increased the chances of having twins is “speculation”, Ashiru warns.

Vice-president of the Southern African Society of Reproductive Medicine and Gynaecological Endoscopy, Dr Sulaiman Heylen, said it is unknown whether yams can increase the chances of a twin birth.

“There is no scientific evidence that yams, or any other product or food, can increase a woman’s chances of having twins,” Heylen told Africa Check.

Okra Leaves

“There are so many twins because of the okra leaf that we eat,” said 15-year-old Kehinde Oyedepo, one of the twins, repeating a view commonly held in the town.

The leaves are used to make a stew that is popular in Igbo Ora. The women who sell piles of okra leaves at a town market are quick to agree.

They said local traditions over how the leaves are consumed were crucial. For example, a stew made from the leaves should be eaten immediately and never stored.

Oyenike Bamimore, who sells the bread, said she was living proof that the diet was the cause. “Because I eat okra leaves a lot, I gave birth to eight sets of twins,” she said.

Conclusion

Ekujumi Olarenwaju, an obstetrician gynaecologist based in Lagos, around 100 miles (160 km) away, believes the causes of the phenomenon lie elsewhere because the same kind of yam is eaten elsewhere in the world without the same result.

“Thus far scientifically, no one can say this is the reason,” said Olarenwaju. “One of the plausible reasons is the hereditary aspect of it because maybe over the years they inter-marry, they now have that gene being pooled and concentrated in that environment,” he said.

I’m no genetic scientist, but I say it’s worth a try if you really want multiples. At least consciously incorporating more yams in your diet does you no harm, and besides it’s better than some dangerous tips advocating progesterone creams, and the prescription drug clomidto conceive twins.

Obviously this is not a fool-proof way to try and have twins as nobody knows how much yam one has to eat. Also, it’s uncertain whether the effects of eating yam on a woman trying to conceive are immediate or cumulative. Most importantly, nobody has provided any specific explanation or medical evidence that could prove that yam consumption can cause multiple births.It’s pure speculation.

While eating a plate full of yams every day may be just plain silly but at least it has no real negative effects, and there is no harm in trying. You may just get lucky.