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Can too much alcohol bring on dementia?

Alcohol consumption, especially heavy and long-term drinking, has been linked to an increased risk of dementia. However, the exact relationship between alcohol and dementia is complex and not fully understood. Here we explore some key questions around alcohol and dementia.

What is dementia?

Dementia is not a single disease, but rather a group of symptoms caused by various diseases and conditions that affect the brain. It involves decline in cognitive functions such as memory, language, problem solving and attention. Alzheimer’s disease is the most common cause of dementia, accounting for 60-80% of cases. Vascular dementia, dementia with Lewy bodies and frontotemporal dementia are other common causes.

How might alcohol contribute to dementia risk?

Heavy alcohol consumption over the long-term has been associated with an increased risk of all types of dementia. Several potential mechanisms have been proposed for how alcohol could promote dementia:

  • Chronic heavy drinking can lead to vitamin and mineral deficiencies, particularly thiamine, that may contribute to cognitive decline.
  • Alcohol consumption elevates homocysteine levels, which are linked to vascular disease in the brain.
  • Alcohol can interact with medications commonly taken by older adults, exacerbating cognitive impairment.
  • Heavy drinking may contribute to development of other medical conditions like diabetes, hypertension and liver disease that indirectly increase dementia risk.
  • Alcohol may promote neuroinflammation and neuronal damage through oxidative stress.

Is the relationship dose-dependent?

Studies indicate the association between alcohol and dementia risk appears to be dose-dependent – in other words, the risk increases with the amount consumed. A meta-analysis published in 2014 looked at over 365,000 participants and found:

  • Light to moderate drinking (1-3 drinks/day) was not associated with increased risk.
  • Heavy drinking (3-4 drinks/day) was associated with 1.5 times the risk.
  • Very heavy drinking (4+ drinks/day) had over 3 times the risk.

Binge drinking also appears to increase dementia risk. An analysis of over 1 million adults found dementia rates were nearly 2 times higher in those reporting heavy episodic drinking.

Is any type of alcohol better or worse?

Most studies do not distinguish between different alcoholic beverages. However, some research suggests certain patterns may be more detrimental when it comes to dementia risk. A study published in 2018 had over 9,000 participants tracked for a 23-year period. The researchers found:

Beverage Type Dementia Risk
Beer (over 3 drinks/day) 2 times higher
Spirits (over 3 drinks/day) 4 times higher
Wine (under 3 drinks/day) No increased risk

This suggests spirits may confer higher dementia risk, while moderate wine drinking does not appear to increase risk. However, more research is still needed.

Does the timing of drinking matter?

Some research indicates that only recent and current alcohol intake is linked to dementia risk. For example, a study in over 1,300 adults found:

  • Heavy drinking only later in life was associated with 3.6 times higher dementia risk.
  • Long-term abstinence from alcohol was not associated with increased risk.
  • Only ongoing heavy drinking was linked to faster cognitive decline.

This implies that reducing heavy drinking, even later in life, may help lower dementia risk compared to continuing heavy alcohol consumption.

Is the relationship different for Alzheimer’s specifically?

Heavy alcohol intake has been most consistently linked to increased risk of vascular dementia, likely due to its effects on blood pressure, stroke risk and heart disease. The evidence for increased risk of Alzheimer’s dementia is more mixed. A meta-analysis published in 2014 reviewed over 20 studies and concluded:

  • Heavy drinking was associated with a significant increased risk of Alzheimer’s.
  • Light to moderate drinking did not show an increased risk.

However, a more recent 2018 study did not find a link between alcohol consumption and Alzheimer’s once vascular dementia was accounted for.

Does moderate drinking help protect the brain?

Some studies have suggested light to moderate drinking may protect against dementia. However, recent research challenges this concept. A 2018 study found no beneficial effect of light drinking versus abstinence on risk of dementia. And a 2022 study showed low to moderate drinking provided no protection against cognitive decline.

Any potential beneficial effects are likely offset by other negative impacts of alcohol on overall brain health. At this time, there is no compelling evidence that any level of drinking prevents age-related cognitive decline or dementia.

Conclusion

In summary, heavy alcohol consumption, particularly over the long-term, is associated with an increased risk of dementia. The relationship appears to be dose-dependent – the more alcohol consumed, the higher the risk. Binge drinking and drinking later in life also increase risk. There is some evidence spirits confer greater risk than other drinks. Reducing heavy drinking may help lower dementia risk compared to continued alcohol abuse, even later in life. At this time the evidence does not support any protective effect of low to moderate alcohol intake against dementia or cognitive decline with age.