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High-calorie diets make recovery hard after attack

May 21, 2019 19:24 IST

'You need to apply a total health approach to maintain cardiac health.'
P Rajendran reports from New York.

Image: Kind courtesy Mohammed_Hassan/Pixabay.com

Age could make it harder to recover after attack due to a high-calorie, fat-rich diet, according to new research conducted by Ganesh Halade and his team at the University of Alabama Birmingham.

High-calorie diets are common in countries like the US, and is an increasing problem in India, too.

Dr Halade's research has huge implications, particularly for older people living on such a diet.

In a paper about their study, which appeared in the FASEB Journal, the team described how an obesogenic diet (OBD), a diet high on calories and fats, changed the kind of bacteria seen in the mouse gut.

Later, when heart failure was surgically induced in the animals, fat diet amplified inflammation in aging after heart attack, noticed with altered ratio of white blood cells -- part of the body's army against invasion -- shifted when heart failure was induced in the mice.

In young mice fed a standard, healthy mouse diet, lymphocytes and neutrophils made up 40 and 44 percent, respectively, of the immune cells.

Young mice given an obesity-causing diet saw their neutrophil percentage shoot up to 62, and while their lymphocytes sank to 29 percent.

An increase in neutrophils is a sign of high inflammation.

Oddly enough, older mice getting a standard diet also appeared have limited change in neutrophils and lymphocytes at levels linked to inflammation (47 percent and 53 percent, respectively).

Like young, old mice given an OBD diet showed similar numbers with marked increase of neutrophils to 68 percent with lower levels of lymphocytes to 32 percent.

In short, age and diet interaction appears to have a big role in how the immune system responds to diet.

 

When heart failure was surgically induced in the animals, the team found that an obesity-causing diet also affected the spleen, causing a reduction in certain white blood cells, called macrophages that played a role in repairing tissues and fix inflammation.

The spleen of all the older mice given the obesity-inducing diet also showed structural alternation.

"When there is injury, the circulatory system sends leukocytes to heal wounds... The spleen also sends an army of leukocytes for major body injury like heart attack or stroke," Dr Halade told Rediff.com

The team also found that an obesity-generating diet caused a sharp increase in Allobaculum bacteria in the intestines.

The increase in Allobaculum has been previously been linked to changes in diet.

Together, the results appear to show that an obesity-inducing diet increased neutrophils, a sign of inflammation, the change being influenced both by age and the composition of intestinal bacteria.

"One precise human application here is that other many studies used mice which are young. We used aging animals 18 months (and older to replicate conditions in humans of the) 55 to 65 years age group," Dr Halade said.

Dr Ganesh Halade

According to him, American diet have shifted to a omega 6 fatty acids enriched proinflammary diet, found in safflower, sunflower, corn and other oils.

Omega 6 fatty acids comprised of linoleic acid that is converted to arachidonic acid in the body and finally to prostaglandins and thromboxane after injury, which are associated with inflammation.

Prostaglandins cause blood vessels to swell and cut down unnecessary clotting, while thromboxane has the opposite effect.

"The old mice fat metabolic capacity altered, thus aged mice failed to handle fat enriched diet than younger mice," Dr Halade said.

"When we give them high amounts of fatty acid, the enzymes working on them get exhausted or impaired. He added that while these enzyme levels are disrupted by enriched fats in the diet likely cause network imbalance in heart failure syndrome.

High omega 6 fatty acids also alter the omega 3 fatty acids like docosahexaenoic acid (DHA), necessary for human brain and retinal function), or fish or algal oil, are less likely to cause damage.

Dr Halade, a native of Nashik, Maharashtra, earned his bachelor's degree in pharmacy at the North Maharashtra University, went on to get a master's degree at the Birla Institute of Technology, and then a PhD from the Institute of Chemical Technology in Mumbai.

It was during his first stint as a postdoctoral fellow at the University of Texas Health Science Center at San Antonio, that he began working seriously with fats.

"I was doing my post-doc with Gabriel Fernandes, and I learned the nuances of fats. That was fascinating. It was not just about diet, but what molecules they go on to make."

Working later with another cardiovascular mentor, Merry Lindsey, Dr Halade studied how fats influenced recovery from heart attack in obese animals.

Bolstered by those experiences, he went on to become an assistant professor at the University of Alabama, Birmingham.

Summing up his research, Dr Halade said, "If you give balance fat intake, it makes different molecules that are safer. Fat is essential, but the quality is important."

Like the American Heart Association did, he recommended the use of avocado or oil enriched omega-3 fats for older, more susceptible, people."

As he put it, "Even if you put the best gas in your car, but the car is 30 years old, it can't go uphill. Likewise, you need to apply a total health approach to maintain cardiac health."

P RAJENDRAN / Rediff.com
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