Why we need to eat bitter foods – and the truth about the loss of this essential taste from our diet

Success may smell sweet, and revenge sweeter still, but can bitter sometimes be better? When it comes to the food we eat there’s a burgeoning body of opinion that says ‘yes’. According to experts, we are in danger of losing an important facet of our palates: the appreciation of bitter tastes. In so doing we are missing out on nutrients that may be key to good health.

Whether it’s down to our increased consumption of sugary convenience foods or a loss of traditional ways of cooking – such as soups and stews, which balance bitter flavours with other tastes – the fact is that the foods on our supermarket shelves are sweeter and milder than they once were.

The bitter foods we used to eat

Chef, writer and bitter foods evangelist Jennifer McLagan recalls the white grapefruit of her youth: “My mother would dust it with a sprinkling of sugar, but it was still bitter. Today when I go to the supermarket it’s much harder to find a white grapefruit; the preference these days is for pink or red, sweeter varieties.”

Some of us may recall ‘salting’ aubergine to strip them of their bitter tang before cooking. Yet how many of the varieties we eat today require pre-salting? There are even types of ‘mild’ Brussels sprout, being actively marketed towards children.

Growers de-bittering their crops
Bitter foods Aubergine flickr Ruth Hartnup
Aubergine: now rarely need salting before cooking

It’s not just that we are opting for sweeter strains of fruit and vegetables but that producers are actively breeding out more bitter crops, says science journalist Marta Zaraska, author of Meathooked: The History and Science of Our 2.5-Million-Year Obsession With Meat, who has written extensively on the topic of bitter foods.

Also: three reasons not to eat kale

“Food producers are breeding fewer bitter cultivars,” she says. Not only are they removing bitter compounds in the foods they grow but they are also ‘de-bittering’ products that reach our shelves.

Zaraska explains: “In the industry lingo, de-bittering is what you do to remove the bitterness from things like fruit juices.”

Meanwhile, some botany experts suggest that organic and heritage crops may be higher in bitter phytochemical content because those compounds act as a ‘natural’ self-defence against pests – although there is as yet insufficient evidence.

‘So what?’ you may think. But these bitter chemicals may have significant health benefits.

The benefits of bitter taste

Take naringin, a bitter phytochemical (or ‘plant chemical’) found in a fruit such as grapefruit. The use of de-bittering resins can remove as much as 78 per cent of naringin from grapefruit juice.

Yet lab studies have shown naringin to be an effective anti-inflammatory, with antioxidant properties. A 2013 study from China’s Chongqing Medical University showed naringin to inhibit cell growth in certain breast cancer cells. A 2012 study from Riyadh’s King Saud University concluded that it inhibits the proliferation of human cervical cancer cells.

Bitter foods Blueberries flickr Jevgenijs Slihto
Blueberries are high in flavonoids

The bitter phytochemical quercetin – a flavonoid found in foods such as cider apples, dark chocolate, lingonberries, ‘highbush’ blueberries, black olives, capers and cloves – has in early lab studies been linked with a lower risk of cancer, and found to be beneficial for heart health. It may also help to reduce prostate inflammation.

Other key bitter phytochemicals include epicatechin, found in greater amounts in blackberries, broad beans, cider apples (again) and black or green tea. There is also genistein, in soya beans, and the glucosinolates that give the characteristic bitterness to brassica such as Brussels sprouts, kale, watercress and wasabi.

Bitter foods Brussel Sprouts flickr krgjumper
The bitter compound in Brussel sprouts enhances our antioxidant systems

Zaraska adds: “Some tomatoes in Peru have very high levels of the bitter glycoalkaloid tomatine (up to 5,000 mg/kg dry weight). Tomatine can have, for example, cholesterol-lowering effects. Yet sweet tomatoes commonly available in our supermarkets have about 30 mg/kg.”

Why we need bitter tastes

Dr Duane Mellor, assistant professor in dietetics at the University of Nottingham, and a British Dietetic Association spokesperson, says the way these bitter compounds work in the body is not yet fully understood.

But he reports: “We do know some of these bitter compounds can have positive health effects. It’s possible they give a mild ‘prod’ to the body’s own defences, enhancing our own antioxidant systems. Another theory is that they work by boosting enzymes that can help to protect the body’s cells.”

While more research is needed to test their effect on the human body, he says: “In the test tube you can stop cells dying or stop cancer cells growing by adding many of these bitter compounds.”

Bitter foods Dark chocolate flickr Gail
There are beneficial phytochemicals in dark chocolate

Although these nutrients may not be ‘vital’ for us to live – in the way proteins, vitamins and minerals are – there is mounting evidence that they are beneficial, adds Dr Mellor. “With de-bittered varieties of veg you’ll survive, but it’s probably not as beneficial as having those bitter compounds.”

The phytochemicals at play aren’t merely present in greenery, either, he notes; they are also plentiful in cocoa (“the dark, bitter kind”), coffee and even beer (though clearly vegetables are the better option).

“Many of us enjoy the bitterness of coffee and chocolate but not so many feel the same about Brussels sprouts,” says Dr Mellor. “Probably this is more about our view of the food – the whole culture of ‘not liking’ sprouts, whereas there isn’t a culture of not liking chocolate. If you think about it, we’re happy to eat pickled cabbage with a kebab.”

How to get more bitter taste 
Bitter foods Kale flickr Jennifer
Adding kale to your diet boosts enzymes that can help to protect the body’s cells

Easy ways of increasing bitter foods in our diet include combining them with sweeter ingredients: “Perhaps add some kale or Brussels sprouts to a carrot soup. It might look a funny colour but it will taste nice and mild.”

With many herbs and spices high in bitter phytochemicals, he continues, a return to “old-fashioned ways of eating stews and broths” may also help to increase the number of bitter foods we eat, and re-wean us on to them.

Jennifer McLagan’s book Bitter: A Taste of the World’s Most Dangerous Flavour explores the culinary benefits of using these foods: “It’s about re-educating your taste buds and adding a depth and complexity to what we’re eating.

“We’ve swung towards everything being sweet, so bitter comes as a shock and we think we don’t like it. Even coffee is full of sugar, cream, caramel.”

As basic first steps, McLagan recommends grilling radicchio – a bitter chicory – with cheese; coating dark chocolate truffles in cocoa powder rather than chocolate or icing sugar; switching mild, large-headed broccoli for broccoli raab (or rapini); and adding a chunk of orange zest including the white pith to a beef stew, then removing it before serving.

Wild food pioneer Miles Irving is similarly evangelical about bitter, espousing the joy of a good dandelion or sow thistle salad – both plants we can find growing liberally in our own back gardens.

“Bitter leaves are salad for grown-ups,” he says. “They’re challenging and good. The food industry is trying to turn us back into babies. Don’t be a baby.”