Mediterranean diets may keep prostate cancer and Alzheimer's at bay

The diet prioritizes green leafy vegetables like spinach, kale and collard greens


Scientists have come forth with findings that report the importance of Mediterranean diets, or diets rich in vegetables and fruits with fish, in keeping serious diseases such as prostrate cancer and Alzheimer's disease at bay.

Mediterranean diet is primarily a plant-based eating plan that includes a daily intake of whole grains, olive oil, fruits, vegetables, beans and other legumes, nuts, herbs, and spices.

Other foods like animal proteins are eaten in smaller quantities, with the preferred animal protein being fish and seafood.

A study, published in the journal Neurology, has found that people who consume MIND and Mediterranean diets may have fewer signs of Alzheimer's disease - amyloid plaques and tau tangles in their brain - than people who do not consume such diets.

While they are both similar diets, the MIND diet prioritizes green leafy vegetables like spinach, kale and collard greens along with other vegetables.

While this study exhibits an association of a regular consumption of such diets with fewer Alzheimer's disease plaques and tangles, it does not establish a causative relationship.

"These results are exciting - improvement in people's diets in just one area - such as eating more than six servings of green leafy vegetables per week, or not eating fried foods - was associated with fewer amyloid plaques in the brain similar to being about four years younger," said study author Puja Agarwal of RUSH University in Chicago, US.

The study involved 581 people with an average age of 84 at the time of diet assessment who agreed to donate their brains at death to advance research on dementia.

Participants completed annual questionnaires asking how much they ate of food items in various categories.

The participants died an average of seven years after the start of the study.

Right before death, the study found that 39 per cent of participants had been diagnosed with dementia.

When examined after death, 66 per cent met the criteria for Alzheimer's disease, the study said.

At autopsy, the researchers examined participants' brains to determine the amounts of amyloid plaques and tau tangles.

The researchers then surveyed the questionnaires regarding their diets collected over the follow-up period and rated the quality of the diet followed by each person.

When looking at single diet components, the researchers found people who ate the highest amounts of green leafy vegetables, or seven or more servings per week, had plaque amounts in their brains corresponding to being almost 19 years younger than people who ate the fewest, with one or fewer servings per week.

"Our finding that eating more green leafy vegetables is in itself associated with fewer signs of Alzheimer's disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet," said Agarwal.

"Future studies are needed to establish our findings further," said Agarwal.

A limitation of the study was that participants were mostly white, non-Hispanic, and older so the results cannot be generalized to other populations.

Another research by University of South Australia, Australia, has found that men who consume colourful fruits and vegetables on a regular basis are less likely to be diagnosed with prostate cancer (PC). The study is published in the journal Cancers.

A rainbow of foods rich in certain micronutrients helps to prevent PC as well as speed up recovery among men who undergo radiation treatment for the disease, the study said.

The findings highlighted the importance of a Mediterranean or Asian diet that includes these foods.

Researchers in this study compared micronutrient plasma concentrations of prostate cancer patients with a healthy control group, revealing low levels of lutein, lycopene, alpha-carotene, and selenium in PC patients and high levels of iron, sulphur, and calcium in the same group, relative to controls.

Increased DNA damage after radiation exposure was also associated with low lycopene and selenium in blood plasma, the study said.

Men with plasma concentrations lower than 0.25 micrograms (ug) per millilitre (mL) for lycopene and/or lower than 120ug/L for selenium have an increased risk of prostate cancer and are likely to be more sensitive to the damaging effects of radiation, the study found.

Foods that are rich in lycopene include tomatoes, melons, papayas, grapes, peaches, watermelons, and cranberries. Selenium-rich foods include white meat, fish, shellfish, eggs, and nuts.

Prostate cancer remains one of the most common and fatal cancers in men, but the nutritional deficiencies associated with it remain largely unknown, hence this study, it said.