Researchers have said daily intake of bitter leaf with Nigeria’s indigenous staples or as a spice in food may help to promote weight loss and lower bad cholesterol levels in the blood by decreasing the amount of dietary fat that is absorbed in the intestines.
In a new study, adding bitter leaf to the diet had a lowering effect on bad and total cholesterol concentration at both 5% and 10% dietary incorporation levels under laboratory conditions in animals.
Administration of methanol extract of Vernonia colorata at 1000mg/kg and 200mg/kg significantly downregulated weight gain in animals fed a high-fat diet relative to the untreated group that was fed a high-fat diet only.
Experts, in the study, said bitter leaf may be useful in weight loss regimen, reducing dietary obesity and also serve as a potential drug lead in the search for natural products for the treatment of diseases associated with dyslipidemia, a condition in which there is abnormally high cholesterol or fat in the blood.
The study assessed the effect of feeding both a high-fat diet (HFD) and methanol extracts of Vernonia colorata (MEVC) on lipid profile (amount of cholesterol and fat in the blood) and body weight changes in 30 Wistar albino male rats aged between 10 and 12 weeks.
It was in the 2021 edition of the journal, Biokemistri. It involved Ijeoma Nina Eke-Ogaranya and Anthony Chibuzor Nnamudi at the PAMO University of Medical Sciences, Port Harcourt, Rivers State, in collaboration with Ifeoma Irene Ijeh at the Michael Okpara University of Agriculture, Umudike, Abia.
Different amounts of the extract of Vernonia colorata were administered orally on a daily basis. Body weight was measured weekly while the amount of cholesterol and fat in the blood was measured at the end of the study which lasted for 10 weeks.
The study found that the bad cholesterol and fat lowering effects of extracts of Vernonia colorata were similar to Orlistat, the drug designed to treat obesity. It also resulted in a dose-dependent decrease of 22.2% and 15.8% in body weight of animals that were administered 1000mg/kg and 200mg/kg of methanol extract relative to a 12.5% decrease in the Orlistat group.
There was a significant decrease in LDL cholesterol concentration upon concomitant feeding of a high-fat diet and administration of methanol extract of Vernonia colorata relative to the high-fat diet control group.
Obesity is a complex disease involving an excessive amount of body fat. Obesity isn’t just a cosmetic concern; it’s a medical problem that increases the risk of other diseases and health problems, such as heart disease, diabetes, high blood pressure and certain cancers. High-fat foods rich in cholesterol and triacylglycerols have been implicated in these conditions.
Although there are genetic, behavioural, metabolic and hormonal influences on body weight, obesity occurs when there is overeating, especially in high-fat foods and physical inactivity. So, many therapies, therefore, target achieving weight reduction through dietary modulation.
Vernonia colorata is a perennial shrub that is found throughout Central and West Africa. It has broader, wildly hairy leaves and it is less bitter-tasting than Vernonia amygdalina. Hence, it can be described as a sweet-bitter leaf due to its characteristic non-bitter taste.
Vernonia colorata is similar to Vernonia amygdalina (commonly referred to bitter leaf, onugbu or ewuro), in appearance and nutrient content. They share many of the vernacular names and uses are the same.
Bitter leaf is commonly used in traditional medicine. Leaf decoctions are used to treat fever, malaria, diarrhoea, dysentery, hepatitis and cough as a laxative and as a fertility inducer. They are also used as a medicine for scabies, headache and stomachache. In Nigeria, its leaves are placed on a wound as a substitute for iodine.
Vernonia colorata is suggested to stimulate cholesterol-lowering activity, thereby ensuring the conversion of more cholesterol into bile acids, thus resulting in the reduction of total blood cholesterol level due to increased excretion.
According to the study, “The dose-dependent steady loss in weight could have been as a result of the presence of anti-nutritional factors such as saponins in Vernonia colorata which may reduce lipid distribution and nutrient availability by delaying the absorption of fats in the intestines.”
Previous reports state that regular intake of the bitter leaf also protects the vital organs from damage due to toxicity from poisonous substances. A study published in the Journal of Food and Nutrition Sciences demonstrated how bitter leaf could be used to prevent kidney, liver and heart damage.
According to the study, the ethanol leaf extract of Vernonia amygdalina ameliorates and protects the liver, kidney and heart of male albino Wistar rats against theobromine induced toxicity and modulates the adverse effects on lipid profile.
Also, researchers from the Department of Biochemistry, Delta State University, Abraka, in a study, published in the International Journal of Veterinary Science and Medicine, indicated that administration of bitter leaf extract offered defence against the induced negative effects of crude petroleum and ameliorated and restored the lost kidney function capabilities.
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