Both of these appear on every international list of changeable dementia risk factors.

Neither is written about honestly very often. Smoking advice tends toward lecturing, and alcohol advice has spent two decades being confused by a study finding that turned out to be weaker than it looked.

So here is the plain version, with somewhere to go at the end.

Does Smoking Affect Memory?

Yes. Smoking is named in both the World Health Organization's guidance and the Lancet Commission's list.

The mechanism is not mysterious. Smoking damages blood vessels, including the very small ones that feed the brain, and it raises the risk of stroke. It also increases oxidative stress and inflammation.

The brain depends on a steady, generous blood supply. Anything that narrows those vessels over decades shows up eventually in how well you think.

Is It Too Late to Quit?

No, and this is the part worth knowing.

Risk associated with smoking declines after stopping. People who quit move toward the risk profile of those who never smoked, and this holds for people who quit later in life.

That is a genuinely different message from the one most smokers over sixty have absorbed, which is that the damage is done and there is no point.

There is a point.

Where to Get Help Quitting

Most people who quit successfully have tried before. Previous attempts are practice, not evidence that you cannot.

Call 1-800-QUIT-NOW (1-800-784-8669) to reach your state's quitline. It is free, and it connects you with a trained counselor, a personalized quit plan, and information about medications that help.

Counseling combined with medication works considerably better than willpower alone. Ask your doctor about both together rather than choosing between them.

How Much Alcohol Is Too Much?

Heavy drinking is clearly harmful to the brain, and that part has never been in dispute.

It damages brain tissue directly, interferes with vitamin B1 absorption in a way that can cause severe memory damage, disrupts sleep, raises blood pressure, and increases the risk of falls and head injuries.

Heavy drinking appears on the Lancet Commission's list of changeable risk factors.

Alcohol also interacts with medication. That interaction is a common and badly underappreciated cause of confusion in older adults, particularly alongside sleep aids and anxiety medications.

What About Moderate Drinking?

You have probably read that a glass of red wine protects your brain. That claim deserves a careful answer rather than a confident one in either direction.

It came from observational studies that found moderate drinkers had better outcomes than both heavy drinkers and non-drinkers.

The problem is who ends up in the non-drinking group. It includes lifelong abstainers, but it also includes people who stopped drinking because they became ill. Comparing drinkers against a group that contains people already unwell makes drinking look better than it is.

When researchers account for this, the apparent benefit shrinks considerably.

Guidance has moved accordingly. The World Health Organization's position is that no level of alcohol consumption is safe for health overall.

What that means practically: if you drink moderately and enjoy it, this is not a reason for alarm. But it is not a health measure, and starting to drink for your brain is not supported.

What If Cutting Down Is Hard?

Then it is worth saying so to someone, and that is a practical statement rather than a judgment.

Alcohol dependence is also dangerous to stop abruptly. Withdrawal can cause seizures and requires medical supervision. This is not something to do alone on willpower.

The SAMHSA National Helpline is 1-800-662-4357. It is free, confidential, available 24 hours a day in English and Spanish, and it will connect you with local treatment options.

What Should You Do Next?

If you smoke, the quitline number above is the single highest-value thing on this page.

If you drink and are not sure whether it is affecting you, an honest week of writing down what you actually drink usually answers the question without anyone else being involved.

And if you want to know where your memory stands today, a baseline gives you something to measure against later. Memory Exam is a 10 to 15 minute verbal assessment you can take at home.

Memory Exam is a screening tool, not a diagnosis. Results should be discussed with a qualified doctor or healthcare professional when appropriate.

Where This Information Comes From

  • World Health Organization. Risk reduction of cognitive decline and dementia: WHO guidelines, second edition. July 2026.
  • Livingston G, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. The Lancet 2024.
  • U.S. Centers for Disease Control and Prevention. National tobacco quitline, 1-800-QUIT-NOW.
  • Substance Abuse and Mental Health Services Administration. National Helpline, 1-800-662-HELP (4357).