Grape extracts may protect against colon cancer

Islamabad - Researchers may have just moved closer to a prevention strategy for this condition, as a compound that suppresses colon cancer stem cells is found in grapes. More specifically, the researchers tested the effect of a combination of resveratrol - a polyphenolic compound found in grapes, red wine, peanuts, and some berries - and grape seed extract. As the authors write, the study rests on the theory that “most, if not all, cancerous tumors are driven by [cancer stem cells].”

cancer stem cells are capable of self-renewal, cellular differentiation, and maintain their stem cell-like characteristics even after invasion and metastasis,” explains lead researcher Prof Vanamala.  Prof Vanamala and colleagues examined 52 mice with colon cancer tumours. They divided the rodents into three groups: one group was fed the grape compound combination, another group was fed sulindac (an anti-inflammatory drug previously found to reduce tumours in humans), and one group was given a normal diet.

The researchers found that the number of tumours in the mice that had the grape compound diet decreased by 50 per cent. This drop was similar to the one seen in the sulindac group, but unlike the anti-inflammatory drug, the grape compounds did not cause any gastrointestinal toxicity.

In vitro, the experiments yielded similar results, determining the “molecular basis for the beneficial effect” of the grape compounds on human cancer stem cells.

The study also found that resveratrol and grape seed extract did not suppress cancer stem cells as effectively when taken separately and in small doses. It seems to be the combined effect of the two that produces the best results.

“The combination of resveratrol and grape seed extract is very effective at killing colon cancer cells,” says Prof Vanamala. “And [...] the combination of these compounds is not toxic to healthy cells.” Prof Vanamala suggests that the findings may bring us closer to understanding why cultures that traditionally eat more fruits and vegetables have lower colon cancer rates.

Plant-based diets may provide several key compounds that kill off cancer stem cells, says Prof. Vanamala. He also recommends consuming a large variety of colourful fruits and vegetables to prevent colon cancer and other chronic conditions such as type 2 diabetes.

Prof Jairam K P Vanamala said, “This also connects well with a plant-based diet that is structured so that the person is getting a little bit of different types of plants, of different parts of the plant, and different colours of the plant.

He adds, “This seems to be beneficial for not only promoting bacterial diversity, but also preventing chronic diseases and eliminating the colon cancer stem cells.”

However, Prof Vanamala also adds that more work is needed to fully understand the anti-cancer mechanism behind grape compounds and other extracts in fruit and vegetables.

The researchers hope that their findings will set the stage for human trials that could test the effects of the grape compounds on colon cancer.

If these trials are successful, the researchers hope that the combination of resveratrol and grape seed extract could be taken in the form of a pill; this may protect against colon cancer and prevent the disease from recurring in those who survived the condition. Meanwhile, a new review of studies looking at the health effects of avocados finds that there is “satisfactory clinical evidence” that the fruit can help to treat metabolic syndrome.

Hosseinzadeh and colleagues found that the fruit has the strongest impact on lipid levels - that is, levels of HDL cholesterol, LDL cholesterol, total cholesterol, and triglycerides.

“The reported mechanism of this effect was regulating of the hydrolysis of certain lipoproteins and their selective uptake and metabolism by different tissues such as liver and pancreas,” explain the authors.

“Another possible mechanism could be related to the marked proliferation of the liver smooth endoplasmic reticulum which is known to be associated with induction of enzymes involved in lipid biosynthesis.”

The review also uncovered evidence that avocado is beneficial for weight loss. The researchers cite one study that found overweight or obese adults who ate one avocado every day for 6 weeks experienced significant decreases in body weight, body mass index (BMI), and the percentage of body fat.

Additionally, the team identified a number of studies associating avocado intake with reductions in blood pressure among patients with hypertension, and evidence suggests that the fruit might also help to reduce atherosclerosis - the narrowing or hardening of arteries caused by a buildup of plaque.

Notably, Hosseinzadeh and colleagues found that it is not just the flesh of the avocado that can benefit metabolic health - the peel, seed, and leaves of the fruit may also help.

Overall, the researchers conclude that avocado may be effective for the treatment of risk factors associated with metabolic syndrome, though further research is warranted. They write,

“In this review article, satisfactory clinical evidence suggested that avocado can be used as herbal dietary supplements for treatment of different components of [metabolic syndrome].

Although, avocado like other herbal products is safe and generally better tolerated than synthetic medications, there is limited scientific evidence to evaluate different side effects because of contaminants, or interactions with drugs. Besides, further studies need to be accomplished on the metabolic effects of different parts of avocado for other possible mechanisms.”

This news was published in The Nation newspaper. Read complete newspaper of 01-Jul-2017 here.

Source : http://nation.com.pk/islamabad/01-Jul-2017/grape-extracts-may-protect-against-colon-cancer

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