Bread. I love it. I’ve always prided myself on eating ‘healthy’ bread. Wholemeal or wholegrain. Seeded. 

Then I heard doctor, author and wholefood evangelist Chris van Tulleken, who talks regularly about foods and health, comment that most foods wrapped in plastic are ultra-processed and largely bad for us. Surely that couldn’t mean my wholesome, nutritious loaves, could it?

It was time to investigate.

Spoiler alert: I now bake my own bread. Should you?

The Aladdin’s Cave of supermarket bread

Our supermarket shelves are laden with endless varieties of bread, from ephemeral white ‘plastic’ bread to artisanal loaves. Most of us go for packaged, sliced bread. Our knife skills are often not at their best first thing in the morning when we need a slice of toast to go with our coffee, or when the kids’ sandwiches need to be ready in five minutes. 

Supermarkets know we want our bread to last at least a week. We don’t want to find a house brick or a fuzzy blue mould monster when we reach for the loaf. They also need to churn out bread on a massive scale: 12 million loaves per day in the UK and perhaps 50 million in the US, though published US data is surprisingly limited.

I’m clearly not the only one who enjoys eating bread!

To meet this demand, British industrial bakers in the early sixties developed a process to make bread quickly and efficiently by replacing traditional kneading with rapid mechanical mixing, proving bread in a vacuum, and using additives, so-called dough enhancers. This is the Chorleywood process, and it’s now the way most bread is made.

The Chorleywood process arguably leads to lower-quality bread. Bakers can use lower-quality flour and a higher proportion of water. They also use solid fats (often saturated fats), which are generally less healthy. Then there are the additives.

Of course, what goes into our foods is strictly regulated, so those additives have been well studied. However, the average American eats about fifty-three pounds (24 kg) of bread each year, so those small quantities of additives add up.

Does the Chorleywood process make industrially produced bread an ultra processed food?

What exactly is ultra-processed food?

The NOVA food classification system divides our food into four categories:

1. Unprocessed or minimally processed foods
2. Processed culinary ingredients
3. Processed foods
4. Ultra-processed foods (UPFs)

According to this NOVA classification, ultra-processed foods contain more than five ingredients, including those not typically found in a home kitchen. These might include preservatives, colourings and flavourings. These additives are there to make the products cheaper, longer-lasting and tastier – some would say even addictive.

By these criteria, there’s no doubt supermarket bread may be classified as ultra-processed food.

Now, let’s look at what is added to our bread.

The chemical melting pot of mass-produced bread

If you’re reading this, I’ll assume that, like me, you try to make healthy food choices. So, let’s look at wholemeal bread.

I took a sample of US and UK supermarkets’ most popular wholemeal/wholewheat loaves and noted their additives. We’ll compare them to a typical home-baked loaf containing just five ingredients: flour, water, salt, fat and yeast.

Here’s what I found:

Those ‘healthy’ loaves contain a multitude of additives. 

Should we worry about gluten? 

Wheat gluten tops the list. That makes sense. It’s gluten that gives strength and elasticity to the bread, so if time is of the essence, having more gluten means you can get away with kneading less.

About 1% of the population has an allergic reaction to gluten that can lead to gut damage, rashes and malaise – coeliac disease. For the rest of us, gluten wasn’t a problem until books by William Davis, David Perlmutter, and others convinced millions of us that we are gluten-sensitive and that gluten is a poison that must be banished from our diet. The scientific consensus is that this is largely a myth. You can read more about the gluten scare in an excellent New Yorker article.

Calcium propionate: Potential cereal killer?

Calcium propionate is the next most prevalent additive, added to all but two of our loaves.

Propionic acid is a naturally occurring short-chain fatty acid. Its calcium salt is added to bread to prevent mould growth and prolong the shelf life. Whilst I’m not concerned about added gluten, calcium propionate gives more cause for concern.

At levels found in three slices of bread, calcium propionate can disrupt insulin sensitivity and glucose metabolism, leading to impaired glycaemic control and weight gain. This may lead to an increased risk of developing type 2 diabetes.

Amounts equivalent to five to ten slices of bread have caused acute toxicity in schoolchildren when flour tortillas were made with higher than recommended amounts of calcium propionate and another food additive, potassium bromate.

Given that I eat three or four slices of bread daily, I’d like mine without calcium propionate; thanks!

Emulsifiers are equally common additions to your daily bread. 

Typically, this is in the form of mono and diacetyl tartaric acid esters of mono and diglycerides of fatty acids. Did you get that? Me neither. That’s why it’s often shortened to DATEM or E472e. You might also see them listed as monoglycerides or diglycerides.

Some people have expressed concern about DATEM after toxicity was seen in a rat study conducted by Health Canada. However, it was only seen when the rats’ diet comprised 10% DATEM. That’s a huge amount. It has been estimated that an average man would need to eat around 150 pounds or 70 kilos of bread daily, long-term, to get that sort of exposure. Now I like my bread, but 70 kilos a day feels a bit much.

More reassuringly, extensive testing by the EU food safety authorities and studies of infants receiving high doses of DATEM in breast milk substitutes have shown no findings of concern.

DATEM doesn’t worry me.

Next on our list, vinegar helps to break down wheat protein, strengthens the gluten network, inhibits mould growth and may improve the flavour (think sourdough). There’s nothing to worry about here. In fact, I’ve started experimenting with a teaspoon of vinegar in my own bread making. It does seem to improve the rise but it’s early days. Ask me later.

Ascorbic acid is added to the majority of breads. Otherwise known as vitamin C, while it’s usually an antioxidant, the ascorbate oxidase naturally present in flour converts it to an oxidising agent that can whiten flour and strengthen the bread. A little extra vitamin C never hurt anyone.

Now we’re down to soya flour and palm oil, present in about half of the loaves.

Soya flour improves hydration, which reduces mixing and rising times. Palm oil gives a softer, moister crumb. You can get this effect with any fat or oil, but palm oil is cheap. This bit baffles me. Is it really cheaper to cut down jungle and ship palm oil halfway across the world than to use vegetable oils we produce at home? Something seems wrong there.

I’m not worried about the health effects of soya flour or palm oil, though environmental concerns are another issue. Between 1 in 140 and 1 in 200 people are thought to have soy allergies of varying degrees of severity. If that’s you, soy flour in bread may cause problems.

Caramelised sugars or molasses were added to around a third of the loaves. It’s here to add colour and improve surface browning. I add a little sugar to my own bread, so it’s not a big concern, but there is the Pandora’s box of potentially carcinogenic compounds produced anytime you brown food – think bread, meat, toast, fried onions. That delicious Maillard reaction brings delightful taste with a side of carcinogenesis. Sous vide, anyone?

Soy lecithin was in four of our loaves. It’s another emulsifier stabilising gluten, giving a finer crumb and greater volume. It also increases the shelf-life. Though there’s a risk of reactions in people with soy allergy, the amount of soy protein in soy lecithin is very low, so most experts don’t think it’s a problem for anyone except those with the most severe soy allergies. 

Citric acid and calcium were also added to four of our bread samples.

Citric acid, like vinegar, gives stronger gluten, thus helping the bread rise. It’s the acid in citrus fruits, so there’s no cause for concern.

Calcium sulphate also strengthens the gluten network. Many of us don’t get enough calcium in our diet. Getting a little extra from bread is a bonus.

Two of our loaves contained potassium iodate. This is a controversial one.

Potassium iodate is an oxidising agent. It strengthens gluten and accelerates chemical reactions, leading to a better and quicker rise. It’s banned as a dough-strengthener in the EU, Australia, New Zealand and Canada but allowed in the US. 

Iodine is vital to our health and can be deficient in our diet. Some countries use iodine-fortified bread to avoid deficiency. In the EU and US, iodine is added to salt instead.

Online, you may see scare stories about a 2000 study in which rats developed salivary tumours after being given potassium iodate in their drinking water. However, the animals had been given a cancer-promotor before the study, and they were given so much potassium iodate that they lost weight. There’s no suggestion that potassium iodate harms humans in the amounts present in bread.

We’re approaching the list’s end now, with six additives, each seen in just one loaf. 

Sorbic acid is a preservative that prevents the growth of moulds, yeasts and bacteria. No significant health concerns have been reported.

Just one loaf listed microbial enzymes in its list of ingredients, but that doesn’t mean it’s the only one in which they had been used. 

A legal loophole means that if the enzyme is used to process ingredients before they are put into the bread, they don’t have to be mentioned in the ingredients list. They must be listed on the food labels if they are still active when put into the bread or added as a formal ingredient. That means there could be one of a number of enzymes, such as phospholipase, fungal alpha amylase 9, transglutaminase, xylanase, maltogenic amylase, hemicellulase, oxidases, peptidases and proteases languishing in your loaf. It’s likely they will have been destroyed during baking.

Raisin juice concentrate is used for colouring.

Ammonium sulphate helps control the pH of the dough to improve its rise and may also provide a spot of nitrogen’ fertiliser’ for the yeast. There aren’t any reported safety concerns, though collect enough, and you can make a fertiliser bomb.

Bringing up the rear, we have ‘natural flavours’ and whey.

Natural flavours are defined by the FDA as “a substance extracted, distilled, or similarly derived from natural sources like plants (fruits, herbs, vegetables, barks, roots, etc.) or animals (meat, dairy products, eggs, etc.) via a method of heating, with its primary function in food being flavoring not nutritional.” That’s all very well, but natural flavour mixes can also contain emulsifiers, flavour enhancers, preservatives and solvents. In fact, these other chemicals can make up the vast majority of the flavouring mix. 

There are so many potential ingredients of ‘natural flavours’ that it’s hard to comment on health concerns other than to say that the amounts used are likely to be very small, and all are ‘generally regarded as safe.’

Last but not least, we have whey. Whey improves the texture, slows staling and contributes to browning through our inevitable Maillard reaction.

How do our various manufacturers stack up when it comes to loading their bread with additives?

Here’s how.

Do you see your supplier of choice in there? It does show that we do have a choice, with Sara Lee giving us eleven bonus additives and Whole Foods just four. Remember, our homemade bread has zero – though if my vinegar experiment works out, mine might creep up to one.

Of course, not all additives are made equal. If, like me, the only additive you’re concerned about is calcium propionate, then Whole Foods and Oroweat are the two you should look at.

Finally, I looked at the salt content. 

It’s not technically an additive since it’s in homemade bread, too. If you’ve ever forgotten to add it, you’ll know how disappointing a saltless loaf is.

There’s a three-fold difference in salt content between the saltiest and the least salty, with UK bread being decidedly saltier than their US counterparts and homemade bread sitting around the middle.

There’s a lot of variability between recommended salt intake between countries and the size of an individual slice, but to give you some sense of comparison, it would take around 15 slices of 365 Wholemeal by Whole Foods, seven slices of homemade bread or five slices of Tesco Finest Wholemeal to take you to the US recommended maximum salt intake of 2300mg – assuming you ate nothing else.

After all that research, what did I conclude?

Is supermarket bread really bad for us?

So, is supermarket bread an ultra-processed food? With that industrial processing and additives galore, it certainly is. Should we worry about those extra ingredients?

After looking at all those additives, the only one I’m sure I’d rather not put into my body is calcium propionate, and it was in all the British breads that I looked at. I was also a little concerned about the salt level in UK bread, but I’m not hypertensive and don’t have a high overall salt content in my diet.

Ultimately, I got myself a breadmaker and haven’t bought a loaf of bread since. Fresh, homemade bread tastes so much better. I love that I can experiment with different ingredients and know what I’m eating. No more calcium propionate for me!

Now, I have a new challenge. It’s so damn tasty I can’t stop eating it!

What about you? Do you worry about the relationship between ultra-processed foods and health? Do you pay attention to the ingredients in shop-bought bread? Can I tempt you to start baking your own?

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