Coffee lovers rejoice! New research says the benefits far outweigh the risks

Savour your morning cup of coffee – new research from the UK's National Cancer Institute says even the heaviest coffee drinkers are likely to live longer than those who don’t drink it at all.

In April, pregnant women were warned off coffee altogether by Norwegian researchers who linked consumption of medium to high levels of caffeine during pregnancy with infant weight gain. This led to numerous clickbait newspaper headlines, but it hasn’t resulted in changes to existing guidelines.

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Why? A major limitation of the study is that it failed to adjust for bottle-feeding or breastfeeding, which can affect growth rates, says Tom Sanders, professor of nutrition and dietetics at King’s College London. “Also, the women with the highest caffeine intakes were older, more likely to be poorly educated or obese prior to pregnancy, and to smoke during pregnancy.”

Pregnant women are still advised to limit their caffeine intake to two small cups a day, but for healthy, non-pregnant adults, drinking moderate amounts of coffee can be good.

Coffee beans are rich in polyphenols; they contain higher concentrations of these antioxidants than blackberries or kale. Unfortunately, polyphenols are heat-sensitive and roasting destroys a lot of them, so lighter roasts are a better option than nutty, smoky dark ones.

The type of bean can make a difference, too, as the cheaper robusta bean is higher in beneficial compounds, called chlorogenic acids, than the prized arabica bean. Drinking filter coffee instead of espresso increases polyphenols and removes substances that contribute to “bad” low-density lipoprotein cholesterol.

So, how much coffee is safe? A study at the Harvard TH Chan School of Public Health found no increased risk of death from any cause, including cancer or cardiovascular disease, for people drinking up to six cups a day – although we’re talking about a small cup containing 100mg of caffeine and not a triple shot latte. However more recently researchers at the UK’s National Cancer Institute concluded that even the heaviest coffee drinkers are likely to live longer than those who don’t drink it at all – and that includes those whose preferred cup is decaf or instant.

A coffee bean contains hundreds of different compounds, and recent science shows various benefits. For instance, a 2015 review of 12 studies showed coffee had a protective effect against depression – more than most teas. That is possibly because several of the natural acids in coffee reduce inflammation in the brain.

Other studies have found coffee drinkers have a lower risk of heart disease, stroke, type 2 diabetes, several cancers, including colorectal, breast, uterine and liver, and Parkinson’s disease.

Your cognitive health will also get a boost from coffee: studies link drinking 3-4 cups a day in midlife with a significant reduction in the risk of dementia and Alzheimer’s disease, again most likely because it is blocking inflammation in the brain that can spark a decline.

Even if you already have mild memory impairment, moderate coffee consumption can slow its progress.

There has been some concern about a chemical called acrylamide, which is produced when the beans are roasted. It has been identified as a probable cause of cancer – which is another reason to opt for a lighter roast. However, new research by the World Health Organisation, evaluating 1000 studies, found that there is inadequate evidence that coffee is carcinogenic.

Fears that coffee adversely affects gut health also appear to be unfounded. In fact, the opposite may be true, as studies have shown consumption can increase numbers of beneficial bacteria and improve microbial diversity.

Some people have a gene that metabolises caffeine particularly fast – about four times faster than those with the slow variant of the gene. Slow metabolisers may experience adverse effects, such as high blood pressure and wakefulness if they drink coffee at night.

New Zealanders sip their way through 3.7kg of coffee a person each year, so it pays to remember that caffeine is a stimulant and drinking too much can result in anxiety, headaches, high blood pressure and palpitations. And don’t forget that energy drinks, chocolate and tea are all sources of caffeine, too.

This is an updated version of an article first published in the July 7, 2018 issue of the New Zealand Listener.