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Sugar in the first 1,000 days: what a new study suggests about Alzheimer's risk
A new British analysis links a low-sugar diet in the first 1,000 days of life with a 46% lower risk of Alzheimer's disease. Nothing is proven by this, but the finding is worth a closer look.
Today, prompted by something I have just read, the subject is sugar. Sugar, and the way bacteria metabolise it, is largely responsible for tooth decay, but that is not what this article is about. We will look at the fundamentals of sugar and dental health in detail in a future article. That is a promise.
As I write this, I am eating an ice cream. There is one flavour in the supermarket that would be almost perfect. If it came with dark chocolate instead of milk chocolate, I would buy it far more often. Today is a very hot summer day, over 30 °C. And I expect that ice cream sales in 2026 will set another record. Even as a dentist, and even though I know the short-term as well as the long-term consequences of sugar, I cannot do without it.
What the study found
I would like to share an article I read recently: "Low-Sugar Diet Early in Life Linked to 46% Lower Alzheimer's Risk."
The underlying paper appeared in July 2026 in the journal npj Aging; I first came across it on ScienceAlert. A research team led by Bing Zhang analysed data from 60,394 people in Britain born between 1951 and 1956, all of them participants in the UK Biobank, a large British health database that follows people over decades.
Those who grew up under sugar rationing in their earliest years had, later in life:
- a 27% lower risk of dementia, the umbrella term for conditions involving progressive loss of memory and thinking ability,
- a 46% lower risk of Alzheimer's, the most common single form of dementia,
- an 11% lower risk of depression, and
- a 20% lower risk of anxiety disorders.
No association was found for Parkinson's disease. The timing was decisive: the protective link showed up above all in the first 1,000 days or so, from pregnancy until roughly the second birthday. Sugar restriction that existed only in the womb and ended at birth made barely any difference.
Why this particular generation?
But what makes the article so interesting is the participants, or rather their starting position. These people were not able to decide about their own sugar consumption. Sugar was rationed. They simply had few opportunities to consume it. For children under the age of two, no separate sugar ration was provided at all. In times of shortage it is easy to ban sugar. Today, by contrast, sugar is available to us constantly. Banning it now would be impossible.
Rationing began in 1940 and did not end until September 1953, eight years after the war. Adults were entitled to less than 40 g of sugar per day, children to less than 15 g. From 1953, once rationing ended, average consumption doubled from 41 g to 80 g of sugar per day. Researchers call a situation like this a natural experiment; a US team examined the same window back in 2024 in the journal Science, then with an eye on diabetes and high blood pressure.
What the study does not say
And here is the context that matters: this is an observational study, and the authors themselves call it "quasi-experimental." Nobody was randomly assigned to a group, and nobody's actual sugar consumption was measured. The number of cases is also small: 307 cases of dementia, 123 of them Alzheimer's. And UK Biobank participants are on average healthier and less diverse than the population as a whole.
A single study is an indication, not a proof.
The study shows an association; it does not prove a cause. Anyone who eats little sugar today, or gives their child little, holds no guarantee of health, and anyone who has eaten a lot of sugar has not thereby been given a diagnosis. The finding fits much of what we already recommend, and it deserves to be followed up.
How much sugar is it today?
The Federal Statistical Office of Germany reports 41.2 kg of sugar per person per year for Germany (as of 2023). That works out at around 113 g per day. The Federal Office for Agriculture and Food arrives at 33.2 kg for the 2024/25 marketing year, roughly 91 g per day; both figures describe the quantity available, not what actually ends up in people's mouths. The World Health Organization recommends less than 10% of daily energy from free sugars, which is about 50 g for a 2,000-calorie diet.
However you do the maths, we are well above that, and well above the roughly 40 g of the rationed generations. More precise figures specifically for children under two are unfortunately not available.
What I make of it
Since sugar is the decisive factor in how tooth decay develops, it is something we have to pay attention to.
I am in favour of taxing sugar, and I believe access to sugar should be restricted for young children. That would mean significant restrictions for nurseries, kindergartens and schools. I say this first and foremost because I see every day what sugar does inside the mouth. The fact that more and more is now being learned about its effects on the rest of the body confirms me in that view. If sugar is taxed, though, the tax on vegetables and wholegrain products should be cut sharply, from the already reduced rate of 7% to a symbolic 1%, say.
The political situation has just shifted. A sugar tax is planned in Germany for 2027. The federal government set it in motion in 2026. It will, however, apply only to sugar-sweetened drinks, not to sugar in general.
Is that enough? Yes and no. I think it is a start that was long overdue. But it will not be something society actually notices. Because the sugar this study is about is not only in lemonade.
And yet one has to weigh things up. Adults must be allowed to decide for themselves what is right for them. After all, here I sit with my ice cream. Anyone who is informed, who knows the consequences and has real alternatives, may answer for themselves whether the pleasure is worth it. Bans are not always the better route. What I do consider indispensable is clear, honest information at the point of purchase. For children in their first years of life, however, I see it differently, because they are not the ones deciding.
What you can take away
Even though the study proves nothing, a few things make sense regardless, especially for the youngest:
- Unsweetened tea and water instead of juice or lemonade, particularly in the bottle you take out with you.
- No sweetened drink in the bottle as a way of getting a child to sleep. It is also the most common cause of early decay in baby teeth.
- It is worth glancing at the ingredients list on baby food jars, squeeze pouches and breakfast cereals, because sugar hides there under a great many names.
I am already looking forward to the deep dive on sugar: what exactly does sugar do in the body? Why do we love it so much? What advantage did it give our ancestors? And can we control ourselves at all, or is sugar addictive?
Until next time. Johannes Fernandes
This article provides general information and does not replace individual dental advice.
Sources
- Lian et al. Early-life sugar rationing, brain aging, and long-term neurodegenerative and psychiatric health outcomes: a population-based natural experiment study. npj Aging, 22 July 2026. nature.com
- ScienceAlert. Low-Sugar Diet Early in Life Linked to 46% Lower Alzheimer's Risk, 2026 (secondary source through which I came across the study). sciencealert.com
- Federal Statistical Office of Germany (Statistisches Bundesamt). Sugar consumption per capita worldwide, as of 2023. destatis.de
- Federal Office for Agriculture and Food (Bundesanstalt für Landwirtschaft und Ernährung). Sugar consumption per capita: 33.2 kilograms, 2024/25 marketing year. ble.de
- World Health Organization. Guideline: Sugars intake for adults and children, 2015. iris.who.int
- DAG, DDG and DGE. Quantitative recommendation on sugar intake in Germany, consensus paper, December 2018. dge.de
- Gracner T, Boone C, Gertler PJ. Exposure to sugar rationing in the first 1000 days of life protected against chronic disease. Science, 31 October 2024. science.org. On the ration allowances see also the summary by the National Institutes of Health, nih.gov
- German Bundestag. Reply of the Federal Government to a parliamentary question, printed paper (Drucksache) 21/6290, 21st legislative term, 3 June 2026. Details of the planned levy on sugar-sweetened drinks from 2028. dserver.bundestag.de
- beck-aktuell. Zuckersteuer statt Zuckerabgabe: Planänderung wegen verfassungsrechtlicher Bedenken, 30 June 2026. beck-aktuell.de
Last updated: August 2026
Illustrations: photograph by Johannes Fernandes. Cover image by Claude Opus 5, created with the blog's graphics generator (style V3). Data sources: Federal Statistical Office of Germany 2023, Federal Office for Agriculture and Food 2024/25, WHO 2015, Gracner et al. 2024.
AI assisted with research and structuring (Claude Opus 5). Content and statements have been reviewed and are the professional responsibility of Johannes Fernandes. How this blog is made
