The Framingham Study is a medical study that began in 1948, tracking residents of the town of Framingham, Massachusetts, and later their children and grandchildren. Over 75+ years, it has given us most of what we know about heart disease, stroke risk factors, and more recently, Alzheimer's. Two papers published by Dr. Matthew Pase's team in 2017 present findings that should interest anyone who drinks their first soda of the morning: High consumption of sugary drinks was found to be associated with lower total brain volume and poorer memory.
Two Separate Studies, Two Types of Evidence
It is important to distinguish between the two papers, as they examine different things using different study designs. Mixing them up is a common mistake that leads to misleading headlines.
Study A: Brain Volume and Memory (Cross-Sectional)
The first paper was published in the journal Alzheimer's & Dementia (Pase et al., 2017). This is a cross-sectional study: a snapshot at a single point in time, without long-term follow-up or calculation of future risk. It examined the association between beverage consumption patterns and brain and memory measures:
- 4,276 participants in neuropsychological tests (memory and cognition).
- 3,846 participants who underwent brain MRI scans.
- Food frequency questionnaires to estimate beverage intake.
Main findings of the cross-sectional study:
- High consumption of sugar-sweetened beverages was associated with lower total brain volume. The difference was roughly equivalent to 1.6 years of brain aging among those who drank 1-2 beverages per day, and about 2.0 years of aging among those who drank more than two beverages per day.
- Lower performance on episodic memory tests among consumers of sugary drinks.
- Fruit juice specifically was associated with smaller volume specifically in the hippocampus (the memory area), in addition to lower total brain volume and poorer episodic memory.
Because this is a cross-sectional study, it shows an association, not necessarily causation. It cannot determine that the beverage caused the lower brain volume, nor does it provide any future risk.
Study B: Stroke and Dementia Over Time (Prospective Follow-up)
The second paper was published in the journal Stroke (Pase et al., 2017). This is a prospective follow-up study of about ten years, examining who developed stroke or dementia over the period:
- 2,888 participants aged over 45 for stroke assessment.
- 1,484 participants aged over 60 for dementia assessment.
And here comes the surprising finding, opposite to the headline many remember: The increased risk of stroke and dementia was found among consumers of artificially sweetened beverages (diet/zero drinks), not among consumers of sugar-sweetened beverages.
- Daily consumption of artificially sweetened beverages was associated with a 2.96-fold increased risk of ischemic stroke compared to non-consumers.
- The same consumption was associated with a 2.89-fold increased risk of Alzheimer's-type dementia.
- Sugar-sweetened beverages were not associated with stroke or dementia in this prospective study.
However, the data should be read cautiously. The association between diet drinks and dementia weakened after researchers adjusted for confounding factors like diabetes and high blood pressure. It is possible that part of the association reflects the fact that people with metabolic issues are more likely to choose diet drinks in the first place. This is an observational association, not proof of causation.
What is a Sugar-Sweetened Beverage?
The category includes:
- Regular soda (Coke, Pepsi, Sprite)
- Sweetened iced tea (Lipton, Snapple)
- Sports drinks (Gatorade, Powerade)
- Energy drinks (Red Bull in regular serving)
- Packaged fruit juices
- Sweetened coffee drinks / lattes
- Cocktails, sweet wine
One serving = 250-330 ml. Two glasses a day already qualifies as a "significant drinker."
Why Beverages Specifically, Not Sugar in Food?
An excellent question. The researchers and broader literature offer several possible explanations for the link with sugar-sweetened beverages:
1. Rapid Absorption
Sugar in a beverage is absorbed within minutes, causing a sharp spike in blood sugar levels. Sugar in chewed food is absorbed more slowly. These sharp spikes can damage blood vessels, including the small vessels in the brain.
2. It Doesn't Satisfy
Liquid calories do not create a feeling of fullness like calories from solid food. People who drink sugary beverages tend not to compensate by eating less, so total calorie and metabolic load increases.
3. AGEs (Advanced Glycation End-products)
Prolonged exposure to high sugar levels promotes the formation of AGE compounds, which have been linked in the literature to cellular damage and aging processes. High consumption of liquid sugar may accelerate this process.
4. The Hippocampus is Particularly Vulnerable
The hippocampus, the memory area, is sensitive to metabolic changes and high sugar levels, which may explain why fruit juice was specifically associated with smaller volume in this region.
Practical Implications
Although the evidence is observational and not definitive, the overall picture from these studies and the broader literature supports reducing both types of beverages, both sugar-sweetened and artificially sweetened:
- Gradual reduction: No need to quit soda in one day. Gradual reduction is easier to maintain.
- Swap for alternatives: Water, mineral water, unsweetened flavored water, unsweetened tea, herbal infusions.
- No extremes: An occasional sugary drink at a special event is not dramatic. The recommendation focuses on regular daily consumption.
- Early education: Drinking habits are formed in childhood, so it is advisable to instill good habits from a young age.
Broader Perspective
These studies are part of a broader trend: the recognition that what we drink is no less important than what we eat. For decades, the industry has convinced us that fruit juices are "healthy" and that diet drinks are a risk-free choice. The evidence is more complex: fruit juice was associated with lower brain volume, and in the follow-up study, diet drinks were specifically linked to a higher risk of stroke and dementia.
The cautious bottom line: Water remains the safest choice. It has no calories, no sugar, and no artificial sweeteners, and no study has linked it to brain damage. If there is one simple change worth considering, perhaps it is switching from a sweetened beverage, whether with sugar or artificial sweeteners, to water.
References:
Pase MP et al., Sugary beverage intake and preclinical Alzheimer's disease in the community. Alzheimer's & Dementia, 2017
Pase MP et al., Sugar- and Artificially Sweetened Beverages and the Risks of Incident Stroke and Dementia. Stroke, 2017
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