Low levels of alcohol good for the brain

[Saul]

In Wine, There’s Health: Low Levels of Alcohol Good for the Brain

Friday, February 02, 2018

 

 

Pouring wine

While a couple of glasses of wine can help clear the mind after a busy day, new research shows that it may actually help clean the mind as well. The new study, which appears in the journal Scientific Reports, shows that low levels of alcohol consumption tamp down inflammation and helps the brain clear away toxins, including those associated with Alzheimer’s disease.

 

“Prolonged intake of excessive amounts of ethanol is known to have adverse effects on the central nervous system,” said Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center (URMC) and lead author of the study. “However, in this study we have shown for the first time that low doses of alcohol are potentially beneficial to brain health, namely it improves the brain’s ability to remove waste.”

 

The finding adds to a growing body of research that point to the health benefits of low doses of alcohol. While excessive consumption of alcohol is a well-documented health hazard, many studies have linked lower levels of drinking with a reduced risk of cardiovascular diseases as well as a number of cancers.

 

Nedergaard’s research focuses on the glymphatic system, the brain’s unique cleaning process that was first described by Nedergaard and her colleagues in 2012. They showed how cerebral spinal fluid (CSF) is pumped into brain tissue and flushes away waste, including the proteins beta amyloid and tau that are associated with Alzheimer’s disease and other forms of dementia. Subsequent research has shown that the glymphatic system is more active while we sleep, can be damaged by stroke and trauma, and improves with exercise.

 

The new study, which was conducted in mice, looked at the impact of both acute and chronic alcohol exposure. When they studied the brains of animals exposed to high levels of alcohol over a long period of time, the researchers observed high levels of a molecular marker for inflammation, particularly in cells called astrocytes which are key regulators of the glymphatic system. They also noted impairment of the animal’s cognitive abilities and motor skills.

 

Animals that were exposed to low levels of alcohol consumption, analogous to approximately 2 ½ drinks per day, actually showed less inflammation in the brain and their glymphatic system was more efficient in moving CSF through the brain and removing waste, compared to control mice who were not exposed to alcohol. The low dose animals’ performance in the cognitive and motor tests was identical to the controls.

 

“The data on the effects of alcohol on the glymphatic system seemingly matches the J-shaped model relating to the dose effects of alcohol on general health and mortality, whereby low doses of alcohol are beneficial, while excessive consumption is detrimental to overall health” said Nedergaard. “Studies have shown that low-to-moderate alcohol intake is associated with a lesser risk of dementia, while heavy drinking for many years confers an increased risk of cognitive decline. This study may help explain why this occurs. Specifically, low doses of alcohol appear to improve overall brain health.”

 

Additional co-authors include Iben Lundgaard, Wei Wang, Allison Eberhardt, Hanna Vinitsky, Benjamin Reeves, Sisi Peng, Nanhong Lou, and Rashid Hussein with URMC. Nedergaard maintains research labs at both URMC and the University of Copenhagen in Denmark. The study was funding with support from the Department of Navy’s Office of Naval Research, the National Institute of Neurological Disorders and Stroke, and the National Institute on Aging.

[mccoy]

MMMM...., 2.5 drink/day = about 440 cc of wine daily, close to half a liter (1 drink = one 180 cc glass??)

 

Sounds pretty high for an optimum quantity, considering that some polyphenols-rich red wines are 15% alcohol content. If the munbers are right, that would mean 66 cc pure alcohol per day.

[Sibiriak]

Standard drinking units vary from 8 to 14 grams of alcohol or more, depending on the country.

 

https://en.wikipedia.org/wiki/Standard_drink#Definitions_in_various_countries

 

In the UK, one unit of alcohol is defined as 10 milliliters (cc)  or 8 grams  of pure alcohol.   (In Italy it's 10g.)  A medium glass (175 ml) of 12%  wine contains around two units of alcohol.   

 

https://en.wikipedia.org/wiki/Unit_of_alcohol

 

In the United States, a standard drink contains  14 grams of alcohol.  "This roughly corresponds to a 12-US-fluid-ounce (350 ml) glass of beer, a 5-US-fluid-ounce (150 ml) glass of 12% wine, or a 1.5-US-fluid-ounce (44 ml) glass of spirit."

 

To calculate the number of drinking units  you need too know the grams of alcohol contained in the alcoholic beverage and how to translate % abv (alcohol by volume) into grams of alcohol.

 

To translate volume to mass, you need to know the density. Alcohol density ≈  0.8g/ml.  E.g., wine at 12.5 %  contains 12.5ml of alcohol/100ml x 0.8 g/ml = 10g of alcohol/100 ml. This is about 1 drinking unit (= 10 g).

 

More precisely, pure alcohol has a density of 789.24 g/l (at 20 °C).

 

https://en.wikipedia.org/wiki/Standard_drink

[James Cain]

The full-text of the original research paper is here: https://www.nature.com/articles/s41598-018-20424-y

 

Beneficial effects of low alcohol exposure, but adverse effects of high alcohol intake on glymphatic function

Iben Lundgaard, Wei Wang, Allison Eberhardt, Hanna Sophia Vinitsky, Benjamin Cameron Reeves, Sisi Peng, Nanhong Lou, Rashad Hussain & Maiken Nedergaard

Scientific Reports, volume 8, Article number: 2246 (2018)

doi:10.1038/s41598-018-20424-y

[mccoy]

Thanks Sibiriak for the references. After reading the article (very very fast):

 

• Medium dose is 1.5 g/kg for mice, which equals 7.9 standard drinks/d for a 70 kg person
• Since the authors cite NIH, a US organization, probably they refer to a US quantity of 14 g of alcohol per standard drink
• A medium dose so would be 7.9*14/70= 1.6 g/kg for men, which sounds strange (equal quantity normalized to weight for mice/men????)
• Anyway, a low (hormetic) dose would be 0.5 g/kg for mice and about the same for men
• So an hormetic dosage would be, for a 70 kg human, 35 g of alcohol per day = 35/0.8= 44 ml of pure alcohol
• Now I refer to a strong Italian polyphenols rich red wine. 14.5% alcohol, which means that in one liter we have 145 ml pure alcohol, or 145*0.8 = 116 grams
• 145/44= 3.3 times the hormetic dosage
• So, the hormetic dosage for this strong wine would correspond to 1000/3.3=  300 ml = two 150 ml glasses per day.

The above is not a small amount, by any means. Also, if the wine is good, it would entail a non negligible monthly cost. A pretty good wine here starts at about 20 Euros per liter, or 24 US$ per month, which would mean 240 US$ (or probably more) per month at an hormetic dosage.