Nothing wrong with cranberries

Sure there is nothing wrong with eating cranberries. Although the same thing could be said of consuming any fruits as they are all considered healthy so there is some competition. That might be the reason why the Cranberry Institute felt obliged to provide funding for two recent studies showing the beneficial effects of cranberry consumption on memory and blood flow.

But can you believe the conclusions of studies tainted by respective industry contributions? Read on so you can judge for yourself.

Cranberries might improve cardiovascular health

The Cranberry Institute provided financial support to a recent clinical trial which found that daily consumption of cranberries for one month improved cardiovascular function in healthy men.

The study included 45 healthy men who consumed 9g of freeze-dried cranberry powder equivalent to a cup of 100g of fresh cranberries per day or a placebo for one month. Incredibly, the study found that those consuming cranberries showed significant improvements in flow-mediated dilation of blood vessels already two hours after first consumption and after one month of daily consumption indicating both immediate and long-term benefits. The researchers claimed that consumption of cranberries as part of a healthy diet can help reduce the risk of cardiovascular disease by improving blood vessel function.

Sure there is evidence that links polyphenols from berries with heart health benefits. And as it happens, cranberries are rich in unique proanthocyanidins that have distinct properties compared to polyphenols found in some other fruits.

Cranberries might also improve memory

The Cranberry Institute wanted more good news by financially supporting a study investigating the impact of cranberry consumption on memory and brain function. Past studies have shown that higher dietary flavonoid intake is associated with slower rates of cognitive decline and dementia. And foods rich in anthocyanins and proanthocyanidins, which give berries their red, blue, or purple colour, have been found to improve cognition.

Thus, the commercially funded research team from the University of East Anglia (UK) investigated the impact of eating cranberries for 12 weeks on brain function and cholesterol among 60 cognitively healthy participants between 50 to 80 years old. Again, half of the participants consumed freeze-dried cranberry powder, equivalent to a cup of 100g of fresh cranberries, daily. The other half consumed a placebo.

The study, one of the first to examine cranberries and their long-term impact on cognition and brain health, showed that consuming cranberries significantly improved memory of everyday events (visual episodic memory), neural functioning and delivery of blood to the brain (brain perfusion).

The cranberry group also exhibited a significant decrease in LDL or ‘bad’ cholesterol levels, known to contribute to the thickening or hardening of the arteries caused by a build-up of plaque. The researchers claimed that the potentially improved vascular health may have in part contributed to the improvement in brain perfusion and cognition.

Of course the researchers considered the findings encouraging, especially as a relatively short 12-week cranberry intervention was able to produce significant improvements in memory and neural function. They see it as an important foundation for future research in the area of cranberries and neurological health.

Ocean Spray Inc. also at it

The U.S. cranberry juice giant, Ocean Spray Inc., has spent millions of dollars funding research to try to prove the health aspects of consuming cranberry juice. There has long been a myth that cranberry juice can prevent urinary tract infections (UTIs). Back in the day, before antibiotics were a thing, acidification of the urine was a recommended treatment for UTI. It was believed that because cranberries are acidic, they would make urine more acidic to fight off bacteria. This was attributed to formation of hippuric acid through metabolism of the quinic acid present in cranberry juice.

Unfortunately, later studies reported that the concentration of hippuric acid in the urine was insufficient for an antibacterial effect unless very large volumes of cranberry juice were ingested.

Subsequently, proanthocyanidins present in cranberries as well as blueberries were reported to inhibit binding of the type 1 P-fimbriae of Escherichia coli to uroepithelial cells, preventing bacterial adherence within the urinary tract.

However, researchers from the University of Manitoba found that the two proposed mechanisms for a beneficial effect of cranberries on UTIs had not yet been shown to have a role in human infection.

EFSA and FDA dismisses cranberry health claims

In 2009, Ocean Spray Inc. submitted a health claim for cranberry juice to the European Food Safety Authority (EFSA) supported by several scientific studies. However, the EFSA Panel concluded that the evidence provided was not sufficient to establish a cause and effect relationship between the consumption of Ocean Spray cranberry products and the reduction of the risk of UTIs in women by inhibiting the adhesion of certain bacteria in the urinary tract.

In 2017, Ocean Spray Cranberries Inc. tried again, this time logging a health claim for cranberry juice with the U.S. Food and Drug Administration (FDA). After reviewing the petition and other evidence related to the proposed health claim, the FDA determined that the scientific evidence supporting the claim did not meet the “significant scientific agreement” standard required for an authorized health claim. However, at the same time FDA announced that it does not intend to object to the use of certain ‘qualified health claims’ regarding consuming certain cranberry products and a reduced risk of recurrent urinary tract infection (UTI) in healthy women. As long as a qualifying statement was included on the label stating that FDA has concluded that the scientific evidence supporting this claim is limited and inconsistent.

Not looking convincing?

It’s up to you to decide what you think. As I said in the beginning there is nothing wrong in eating cranberries as they would be as healthy as any other berries.

To help you make up your mind here is a quote from the well known nutrition expert Marion Nestle:

“Without even getting into whether cranberry powder is equivalent to cranberries, whether anyone can eat cranberries without adding their weight in sugar, or whether any other fruit might have similar effects, we should ask whether it makes any sense at all to think that any one single food could boost memory and prevent dementia in the elderly.”

So there you have it.

The Coffee Consumption Genes

Are you desperate for a cup of coffee just now? The urge might be determined by your genes. I almost didn’t believe it when the newspaper reported that scientists had explored the genes of pregnant women to predict the amount of coffee they consume and its potential impact on their pregnancy.

I have been heavily involved in developing elaborate protocols to explore population food consumption in detail. And now all you have to do is look at the genes. So I did some research and it seems to be true that coffee drinking behaviour is at least partly due to genetics, with a specific set of genetic variants affecting how much coffee we drink.

What the researchers found

In the reported findings, researchers at the University of Queensland used a method called Mendelian randomisation which used eight genetic variants that predicted pregnant women’s coffee drinking behaviour and examined whether these variants were also associated with birth outcomes. Current World Health Organization guidelines say pregnant women should drink less than 300mg of caffeine, or two to three cups of coffee per day. However, the researchers through their genetic analyses found that coffee consumption during pregnancy might not itself contribute to adverse outcomes such as stillbirth, sporadic miscarriages and pre-term birth or lower gestational age or birthweight of the offspring.

As a caveat just to be on the safe side, the researchers emphasised that the study only looked at certain adverse pregnancy outcomes, and it might be possible that coffee consumption could affect other important aspects of foetal development. 

This has been known for some time

The important outcome is that genetics can be used to estimate the amount of coffee consumed. This has actually been known for some time. Heritability refers to degree of genetic influence and can vary from 0 (not heritable) to 1 (completely inherited).

A review published in 2010, reported that twin studies had estimated heritability of coffee consumption by comparing monozygotic twins, who share the common familial environment and the same genes, to dizygotic twins, who also share common familial environment but only half of the genetic material. These studies found that heritability of coffee consumption varied from 0.30 to 0.60 in different populations. Heavy consumption, defined as more than 6 cups of coffee daily, had a heritability of 0.77. A few conclusions can be drawn. First, heavy consumers seem to differ from moderate and light coffee users on several accounts. Secondly, heavier coffee users appear to be more influenced by genetics than lighter caffeine users. 

So far the studies confirmed the possibilities of coffee consumption inheritance without identifying the individual genes responsible for such differential inheritance pattern. 

And the complicated stuff

So genetics have long been suspected of contributing to individual differences in coffee consumption. However, pinpointing the specific genetic variants has been challenging. Thus, researchers as part of the Coffee and Caffeine Genetics Consortium conducted a genome-wide meta-analysis of more than 120,000 regular coffee drinkers of European and African American ancestry. They identified two variants that mapped to genes involved in caffeine metabolism, POR and ABCG2 (two others, AHR and CYP1A2 had been identified previously). Two variants were identified near genes BDNF and SLC6A4 that potentially influence the rewarding effects of caffeine. Two others – near the GCKR and MLXIPL genes involved in glucose and lipid metabolism – had not previously been linked to the metabolism or neurological effects of coffee.

The findings suggest that genes drive people to naturally modulate their coffee intake to experience the optimal effects exerted by the caffeine in coffee and that the strongest genetic factors linked to increased coffee intake likely work by directly increasing caffeine metabolism.

But there is more

People who like to drink their coffee black also prefer dark chocolate, a new Northwestern Medicine study found. The reason is also in their genes.

The scientists found that coffee drinkers who have a genetic variant that reflects a faster metabolism of caffeine prefer bitter, black coffee. And the same genetic variant is found in people who prefer the more bitter dark chocolate over the more mellow milk chocolate.

The reason is not because they love the taste, but rather because they associate the bitter flavour with the boost in mental alertness they expect from coffee.

It is interesting because these gene variants are related to faster metabolism of caffeine and not related to taste. These individuals metabolise caffeine faster, so the stimulating effects wear off faster as well. So, they need to drink more. They learn to associate bitterness with caffeine and the boost they feel. When they think of coffee, they think of a bitter taste, so they enjoy dark coffee and, likewise, dark chocolate.

A new era

In the past, when scientists studied the health benefits of coffee and dark chocolate, they had to rely on epidemiological studies, which only confer an association with health benefits rather than a stronger causal link. The new research shows these genetic variants can be used more precisely to study the relationship between coffee and health benefits.

And who knows, in the future there might be other genetic markers found that drive our food consumption behaviour.