Ask Dr Zac: Does freezing your bread actually have health benefits?
Storing bread in the freezer is something people might do for a multitude of reasons - but it turns out it could also have a surprising health benefit.
Welcome to Ask Doctor Zac, a weekly column from news.com.au. This week, Dr Zac Turner explores if freezing bread is really healthier for your gut.
QUESTION: Is it true that freezing your bread makes it healthier because it helps with your gut health? I saw a video on Instagram and now I’m thinking I should be freezing all my bread before making my Vegemite toast! - Summer, 23, Hornsby, NSW
ANSWER: Dear Summer, Thank you for such a great question. I love that you spotted this on Instagram and wanted to know if there is real science behind it.
Believe it or not, there is some truth here, although it is not quite the miracle that social media might make it sound.
The key is something called resistant starch. Normally, when you eat bread, most starch is digested in your small intestine and converted into glucose, which raises your blood sugar.
But when some starchy foods are cooled or frozen, their structure changes in a process known as retrogradation. This means a portion of the starch becomes resistant starch, which is harder for your body to break down.
Instead, it travels to the large intestine where it feeds your gut bacteria. In turn, this produces short chain fatty acids such as butyrate, which support a healthy gut lining and may help reduce inflammation.
Freezing bread and then toasting it later can reduce the blood sugar spike you would normally get compared with eating it fresh. Research shows the effect can be noticeable with homemade bread, but with supermarket bread it is much smaller.
That is probably because added ingredients and processing interfere with the starch changes that freezing usually produces.
Does this mean you should freeze every slice? It certainly will not hurt and you might see a small benefit. But perspective is important. The increase in resistant starch is modest and depends on the type of bread, how it is stored, and how it is reheated.
We do not yet have strong evidence that freezing bread leads to meaningful long-term improvements in gut health. Resistant starch looks promising overall, but it is not a cure all.
A few things to keep in mind:
• Highly processed breads with lots of additives show little effect
• Repeated freeze and thaw cycles reduce quality
• Toasting until the bread is burnt introduces harmful compounds that cancel out any benefit
So, freezing your bread is a harmless little hack that might give your Vegemite toast a small gut friendly edge.
But do not rely on it as your main gut health strategy. For lasting impact, focus on eating more wholegrains, fibre, fruit, vegetables and fermented foods like yoghurt, kefir and sauerkraut. These are the foods that truly transform your microbiome and support long term gut health.
Bottom line: Freezing bread is not nonsense. It may give your toast a modest gut friendly upgrade, but the real power lies in the overall variety and quality of your diet.
Have a tip top day (pardon the pun),
Dr Zac
Got a question? Email askdrzac@drzac.com.au
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Dr Zac Turner is a medical practitioner specialising in preventive health and wellness. He has four health/medical degrees – Bachelor of Medicine/Bachelor of Surgery at the University of Sydney, Bachelor of Nursing at Central Queensland University, and Bachelor of Biomedical Science at the University of the Sunshine Coast. He is a registrar for the Australian College of Rural and Remote Medicine, and is completing a PhD in Biomedical Engineering (UNSW). Dr Zac is the medical director for his own holistic wellness medical clinics throughout Australia, Concierge Doctors.
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Originally published as Ask Dr Zac: Does freezing your bread actually have health benefits?
