All drinks will impact our body one way or another.
Shots, nightcaps, brews and chasers . . . whether it’s a glass of water, an espresso or the finest champagne, all drinks will impact our body one way or another.
Yet, while often we think carefully about how foods affect our health, few of us give the same attention to what we drink.
So, from trendy vegan plant milks’ to whether a daily glass of red really does keep the doctor away, here’s the science behind what drinks mean for our health a lesson in drinkology.
NUT MILKS CONSIST MAINLY OF WATER
THERE has been a huge shift towards plant-based milk drinks (such as almond, oat and soya) in recent years, but they’re not necessarily any healthier than cow’s milk.
For a start, very little of the plant makes it into the drinks. The most popular brands of nut milks typically have only 1 to 2.5 per cent nut content, and are mostly water. This means they do tend to be lower in calories and fat than dairy milk, but they’re also much lower in protein only soya milk and pea milk (which both give around 8g of protein in a typical 240ml glass) really come close to delivering a comparable amount to that found in dairy drinks, which have around 8.4g for the same size serving.
What’s more, nutrients in plant milks they are often fortified with calcium, vitamin D and B vitamins may not be as easily absorbed. It has been found at least 30 per cent of the calcium in cow’s milk is absorbed by the body, in comparison with 20 to 30 per cent absorption of calcium from plant sources, such as almonds and beans.
It means the amount listed on a label is no guarantee of how much you’ll absorb.
THE TRUTH ABOUT UNHEALTHY’ MILK
Dairy is no longer seen by many as the nutritional wonder food it once was.
One reason is its saturated fat content. Eating a diet high in saturated fats is associated with raised levels of LDL, or bad’, cholesterol, the kind linked with cardiovascular disease. However, not all saturated fats are equal; different fatty acids (the building blocks of fat in food) seem to have different effects on the body. Furthermore, milk isn’t that high in fat anyway. Skimmed milk contains a maximum of 0.3g fat per 100g, semi-skimmed milk has a fat content between 1.5g and 1.8g per 100g and whole milk has a minimum fat content of 3.5g per 100g. (Beef mince contains around 15g to 20g fat per 100g and Victoria sponge cake 20g or more per 100g.)
Other than less fat and fewer calories, there is little difference in nutrient content between skimmed, semi-skimmed and whole milk with the notable exception of vitamin A (needed to support healthy vision and the immune system). Vitamin A is found in the fat in milk, so whole milk contains around twice the amount as semi-skimmed milk, and around 50 times the amount in skimmed milk.
Milk also provides other nutrients, such as calcium and small molecules called bioactive peptides which appear to have a beneficial effect on cardiovascular health.
In short, while one component of milk may have a negative effect on our cholesterol levels, others may help to protect the heart.
IT’S SAFE TO DRINK TAP WATER … OR IS IT?
Water supplies contain traces of drugs: from antibiotics and hormones to mind-altering illegal drugs. They get into our water supply through excretion in urine and from agricultural sources drugs given to animals may pass directly into the ground.
Some drugs degrade before they reach us and others are removed during routine water treatments, but water companies are unable to remove all traces. It is not known what health effects this may have.
The risk is likely to be small. However, over a lifetime, the effects may build up. Antibiotic pollution in rivers and soil may be a key factor in bacteria’s resistance to medication.
Tim Spector, a professor of genetic epidemiology at King’s College London, is concerned that even the tiny amounts of antibiotics we’re consuming could be altering our gut bacteria (important for all sorts of aspects of health).
Even bottled water may not be safe; tests have found it contains bacteria that shows signs of having been exposed to antibiotics.
WHY FIZZY WATER MAKES YOU HUNGRY
Many believe the fullness’ caused by sparkling water helps reduce food intake, but there is evidence it may stimulate appetite. Research has found that fizzy drinks increase the hunger hormone ghrelin. This has been found mainly with sugary drinks, but a small increase was found with sparkling water, too.
One theory is that the carbon dioxide in the drinks triggers a message to the stomach to release the hunger hormone. Another possibility is the gas may cause the stomach to stretch, stimulating cells to release ghrelin.
WAKE UP AND SMELL THE COFFEE!
We all know coffee is a pick-me-up. And while the evidence is inconsistent, there have been reports that coffee helps improve our mental performance in the short term and even prevents cognitive decline or dementia in the longer term.
It’s possible something in coffee may prevent proteins such as beta-amyloid, from clumping together in the brain, as in Alzheimer’s disease, though evidence is inconclusive.
As well as increasing alertness, it’s been suggested that coffee may help the body to burn energy stores more quickly in a number of ways.
However, many of coffee’s health effects have also been observed in people who drink decaffeinated, suggesting that other compounds found in coffee beans are also responsible for coffee’s beneficial effects.
Even the smell can give you a boost, according to a U.S study last year. Researchers found business students performed better at an aptitude test after being exposed to coffee aromas (but not drinking it) compared with those not exposed to the scent. They concluded that the smell of coffee can produce a beneficial placebo effect.
ICE? THINK TWICE UNLESS IT’S A G&T
ADDING ice makes for a refreshing drink. Yet studies in Europe and the U.S. show that ice, whether homemade or from machines, can have microbial life in it, including some bacteria, viruses, yeasts and moulds known to cause ill health.
Freezing them doesn’t kill or inactivate them. In fact, outbreaks of norovirus, salmonella, hepatitis A and E. coli have all been linked with ice consumption.
A study of food establishments in Las Vegas in 2011 found that a third of the ice samples collected exceeded safe limits on bacteria concentration, and more than two thirds contained coliform bacteria, which indicate a possible presence of harmful bugs.
However, adding ice to alcohol or carbonated beverages may reduce the risks, according to one study, possibly because the bugs are unfavourably affected by the alcohol or acidic content.
Even orange juice contains alcohol. Picture: Steve Buissinne | Pixabay
GENES MAY CAUSE YOUR HANGOVER
MANY non-alcoholic drinks contain a tiny amount of alcohol too: even orange juice naturally has around 0.05 per cent alcohol.
In an alcoholic drink, one unit is the equivalent of 10ml, or 8g, of ethanol the amount the average adult can metabolise in one hour. After that, there should be little or no alcohol left in the blood. However, some people are more susceptible than others to the harmful effects of alcohol.
For example, people can carry different versions of the two key enzymes that break down alcohol; alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). ADH converts most of the ethanol in the liver to acetaldehyde, a toxic by-product known to cause harm, but this is quickly metabolised by ALDH into a less toxic compound called acetate, which is broken down into carbon dioxide and water and excreted.
A fast-acting ADH enzyme or a slow ALDH enzyme or both could lead to a build-up of acetaldehyde, which can have damaging effects on the body.
Which versions you have of these enzymes lies in your genes. The extent of your hangovers could be a clue. Some people suffer facial flushing or terrible hangovers, often due to fast ADH or slow ALDH enzymes.
This is particularly common in people with East Asian heritage.
Our genes also affect how ethanol tastes. Some find it bitter, others may perceive sweetness. A 2014 U.S. study, published in the journal Alcoholism: Clinical and Experimental Research, identified that these taste differences were linked to different versions of the TAS2R38 gene. Variations in this gene have previously been linked with alcohol intake, with those who have the more sensitive form of the gene drinking less.
A GLASS OF RED WINE CAN’T HURT
ANY amount of alcohol is now associated with a risk of some cancers and cognitive decline.
However, studies assessing its effects often lump all alcoholic drinks together. But is the wine drinker at the same risk of harm as the vodka drinker?
A number of studies have shown that red wine drinkers, in particular, seem to have a lower risk of cardiovascular problems.
However, this observational’ research does not prove definitive cause and effect, and research is ongoing to determine whether wine really has a protective effect.
The main area of interest is polyphenols, compounds that have antioxidant, anti-inflammatory and anti-cancer properties, which come from grape skins and are in far greater quantities in red wine than white.
Main benefits for heart health have only so far been confirmed for women over 55, drinking five units a week the equivalent of around two 175ml glasses of wine; not a daily glass.
* Dr Alexis Willett is a science writer with a PhD in biomedical science from the University of Cambridge. Adapted from Drinkology: The Science Of What We Drink And What It Does To Us by Dr Alexis Willett (Robinson, £13.99), published on Thursday. © Dr Alexis Willett 2019.
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