Curious Cook: Hot summer tidbits


The best flavanols for the diets of the elderly may be in foods like apples, berries, hazelnuts and kidney beans, to name a few. — SUZY HAZELWOOD/Pexels

First tidbit - heat

Wednesday, the 5th of July 2023 was the hottest day ever recorded on our planet, beating the records set the two consecutive days before. According to paleoclimate scientists, this record very probably stretches back to the Eemian period, between 130,000 and 115,000 years ago. Global temperatures then were estimated to be 2C higher than pre-industrial times, and we are currently getting perilously close to matching those temperatures, with all the attendant consequences, such as sea levels 5-8 metres higher than at present, and vast changes in the distribution of vegetation.

This year also sees the return of a weather phenomenon known as El Niño, which caused the last recorded hottest day before this year in 2016. At the time of writing this, the effect of this year’s El Niño is still far from its peak, but the heat record on 5th July 2023 is already 0.27C (or about 2%) higher than the previous hottest day in 2016. Therefore, it is almost certain that we can expect even hotter days this year. Additionally, El Niño tends to cause severe flooding in many parts of the world, while at the same time creating searing heatwaves and droughts in other adjacent regions.

Nobody would wish for it, but it seems the world is potentially likely to once again encounter problems with food production this year, and some of the issues may be significant due to the severity of global warming. We just do not know yet.

Second tidbit – gut scrub

I wish I knew more about the Human Gut Microbiome (HGM) when I was young. It would have made life much easier if I had understood and cared more about the trillions of microorganisms in my gut. At least it would have prevented many debilitating bouts of Irritable Bowel Syndrome and various gut-related issues.

The same situation probably applied to many people as we are more aware of health elixirs for the various organs (e.g, heart, lungs, liver, kidneys, skin, etc) but it was only very recently that there are pills of spores meant to repopulate (or rebalance) the HGM. After many years, the HGM is finally being taken as seriously as the other important organs of the body.

This does not mean we often take good care of the HGM, especially when we eat foods that contain synthetic emulsifiers like Polysorbate-80 (P80) and Carboxymethylcellulose (CMC). Other “natural” emulsifiers such as carrageenan, soy lecithin, sunflower lecithin, guar gum, locust bean gum, etc, are also food additives to be wary about.

Older people generally have decreased digestive functions. — DANIE FRANCO/UnsplashOlder people generally have decreased digestive functions. — DANIE FRANCO/Unsplash

That is because of the function of emulsifiers, which are used to bind oil-loving (hydrophobic) and water-loving (hydrophilic) molecules together, thereby creating a pleasant “mouth feel” for eating while preserving the moisture and freshness of food items. Emulsifiers also enable foods to have an unnaturally long shelf life, which is commercially very attractive for food producers and convenient for consumers.

In the human intestines, emulsifiers act like detergents, because like detergents, they pick up both fat and water molecules indiscriminately and “wash” them away from surfaces. The human intestines are lined with a fragile protective mucus membrane and studies have shown that emulsifiers in foods can scrub away the mucus, leaving a thinner, more porous intestinal structure between the gut bacteria and the bloodstream. In extreme cases, this has led to “leakages” of gut bacteria into the bloodstream and other body cavities, causing inflammation and other diseases, some of which are potentially very dangerous.

If scrubbing away intestinal mucus is not bad enough, most emulsifiers are also known to alter the composition and density of the microbiota mass itself and cause the expression of pro-inflammatory molecules in the HGM.

This is where “natural” emulsifiers may differ from synthetic emulsifiers because a French 2021 study indicated the HGM can recover better from imbalances caused by some natural emulsifiers, but it takes significantly longer to recover fully from damage caused by P80, CMC, and some other “natural” emulsifiers such as carrageenan and various gums.

Of all the emulsifiers in food, the study found that natural lecithins had the least negative impact on the HGM, provided it is not consumed in excessive quantities.

Third tidbit – age-related memory loss & flavanols

A recent paper based on over 15 years of research reported an interesting link between food-derived bioactive compounds called flavanols and age-related memory loss. This study encompassed several other studies, including one where it was found that memory loss is linked to changes in the dentate gyrus, a particular area within the brain’s hippocampus, and another study where mice fed with epicatechin, a type of flavanol, improved memory functions due to enhanced growth of neurons within the hippocampus of the test rodents.

The main study revolved around COSMOS (Cocoa Supplements Multivitamins Outcomes Study), which did a double-blind test of flavanols on over 3,500 healthy elderly adults over 3 years. Half the subjects received daily 500 mg of flavanols (containing 80 mg of epicatechins) and the other half received placebos. Memory tests were done at the beginning, and then at yearly intervals.

The first outcome was that there was no memory improvement in old people who were already consuming adequate amounts of flavanols before the study. The more interesting finding was those old people who had participated in the study with a flavanol-deficient diet improved their memory scores by 16% at the end of the first year, and this improvement was sustained for the next 2 years of the study.

In combination with the other studies, COSMOS suggests quite strongly that age-related memory loss may be worsened by flavanol deficiency, and may therefore be mitigated by the consumption of adequate amounts of flavanols.

The issue therefore may be establishing the best flavanols for the diets of older people. The experiments thus far focused on flavanols based on cocoa beans, such as epicatechin. But other flavanols may also be effective, such as catechins, procyanidins, resveratrol, quercetin, and myricetin. They are found, for example, in teas, apples, berries, pears, plums, grapes, kidney beans, hazelnuts, millet, red wines, etc. We will have to await more studies on flavanols.

In the meantime, if one is elderly and concerned about a lack of dietary flavanols, perhaps the best sources of epicatechins may be unsweetened cocoa powder (but not the alkalised or Dutch-processed powders) and green tea brewed in hot (not boiling) water.

Fourth tidbit – the guts of really old people

A 2016 Japanese paper about age-related changes in the HGM has recently been revisited by the University of Copenhagen, with a focus only on the gut fauna of centenarians (people aged 100 or more). The original Japanese paper was interesting by itself and traced the very significant changes in the bacterial composition of HGMs of people between the ages of 0 to 104 years old. The changes were probably linked to various factors, including the types of food eaten and digestive capacity.

Perhaps the best sources of epicatechins may be unsweetened cocoa powder. — BRANDS PEOPLE/UnsplashPerhaps the best sources of epicatechins may be unsweetened cocoa powder. — BRANDS PEOPLE/Unsplash

For example, older people generally have decreased digestive functions, and food-based bacteria usually blocked by gastric juices and bile acid (eg, Porphyromonas, Treponema, Fusobacterium, and Pseudoramibacter) tended to feature more in the HGMs of older people.

What was curious were the sudden changes in HGM content AFTER the age of 100. For example, centenarians have the highest levels of bacterial families such as Bacteroides and Enterobacteriaceae than people at any other age. Also, people over 90 years old had the highest levels of bacteria from the families of Clostridiaceae and Eubacterium, but the levels dropped suddenly and markedly upon reaching the age of 100, for reasons unknown.

The new Danish study proposed that previous research had focused too much on the bacterial components and not enough on the viruses in the HGM, especially as there is evidence that centenarians have a more diverse virome (virus fauna) in their HGMs than younger people. These viruses specifically target only various bacteria in the HGM, and not normal human cells, and may help to promote their overall usefulness within the gut.

Previous studies have indicated that the HGMs of old Japanese people tended to produce molecules that help the HGM resist pathogenic, disease-causing bacteria, thus probably helping to protect the intestines as a consequence. And it seems that a more protected intestinal system can help people live longer.

The Danish study immediately raises some interesting questions, such as (a) are viromes the only reasons for better resistance to HGM pathogens? and (b) why does it appear that only very old people have such active/beneficial viromes? Maybe there may be some good answers soon.

Ending tidbit

There is an uncomfortably high chance that many people will find this year 2023 memorable but for the wrong reasons. If the first half of the year is anything to go by, many people may find the rest of the year a foretaste of what uncontrolled global warming can really mean. But maybe this is also the year when all countries finally start adopting the urgent measures needed to limit global warming.

We can always hope.

The views expressed here are entirely the writer’s own.

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