1. By Funmi Agbaje

2.  Yam is a versatile vegetable belonging to Discoreaceae family  Starchy, tuberous root of tropical tree  They are a rich source of carbohydrate, dietary fat and minerals and are low in saturated fat  Yams are a primary agricultural and culturally important commodity in West Africa, where 95% of world’s yam crop is harvested

4.  The term ‘Yam births’ has come from the idea that a high consumption of yam is connected to the high incidence of twin births in Nigeria  Many factors have been known to influence twinning rates. Such as: -maternal age-socio-environmental factors - race -seasonal variations -increased use of contraceptives- GENETICS  However recent studies have been conducted, leading scientists to believe yams may play a major role in twinning rates.  Overall, almost 5 percent of all Yoruba births produce twins compared with just around 1.2 percent for Western Europe and 0.8 percent for Japan

5.  Research into multiple births carried out at Lagos's University Teaching Hospital has suggested that a high level of a chemical found in the Yoruba women and the peelings of the tuber could account for the high level of multiple births.  Yams are believed to contain a natural hormone phytoestrogen, which may stimulate multiple ovulation

6.  Data on single/twin births collected from various teaching hospitals in Nigeria  RESULTS: Average frequency of 40.2 per 1000 deliveries for four hospitals ranks among the highest recorded rates of twin births in the world. The maternal age group of 25-29 years had the highest occurrence of twin births, while the lowest was recorded in the 45-49 years age group.

7.  The effects of various yam diets on the reproductive hormones of experimental rats  Control group X rats on yam diet  RESULTS: With the exception of testosterone (which decreased in the rats on yam diets compared with the control) other reproductive hormones showed increases i.e. prolactin, FSH, LH, progesterone, estradiol

8.  Study finds that a woman's chances of having twins can be modified by diet. Gary Steinman, MD, PhD, an attending physician at Long Island Jewish (LIJ) Medical Center in New Hyde Park, New York  He found that that her overall chance is determined by a combination of diet and heredity  He compared the twinning rate of vegan women, who consume no animal products, with that of women who do eat animal products  He found that the women who consume animal products, specifically dairy, are five times more likely to have twins.  The culprit may be insulin-like growth factor (IGF), a protein that is released from the liver of animals -- including humans -- in response to growth hormone, circulates in the blood and makes its way into the animal's milk. IGF increases the sensitivity of the ovaries to follicle stimulating hormone, thereby increasing ovulation. Some studies also suggest that IGF may help embryos survive in the early stages of development. The concentration of IGF in the blood is about 13 percent lower in vegan women than in women who consume dairy.

9.  We cannot ignore the huge role of genetics  Interplay between both  Diet shown to ENHANCE probability of twinning

10.  http://afp.google.com/article/ALeqM5i_IsZNBK7Hf1B4VhfWtF xg7G2svw http://afp.google.com/article/ALeqM5i_IsZNBK7Hf1B4VhfWtF xg7G2svw  http://www.bbc.co.uk/worldservice/people/highlights/01060 7_twins.shtml http://www.bbc.co.uk/worldservice/people/highlights/01060 7_twins.shtml  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2840794/?re port=printable http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2840794/?re port=printable  http://scholarsresearchlibrary.com/ABR-vol3-iss4/ABR-2012- 3-4-1839-1842.pdf http://scholarsresearchlibrary.com/ABR-vol3-iss4/ABR-2012- 3-4-1839-1842.pdf  http://en.wikipedia.org/wiki/Yam_(vegetable http://en.wikipedia.org/wiki/Yam_(vegetable  http://www.eurekalert.org/pub_releases/2006-05/nsij- sft051606.php http://www.eurekalert.org/pub_releases/2006-05/nsij- sft051606.php