Introduction: after all, is alcohol the villain or does it depend on the dose?

For centuries, alcohol has been part of social relationships, religious rituals, and celebrations. However, the negative effects of excessive consumption on the liver—the main organ that metabolizes ethanol—are widely documented. But is all consumption harmful? Or is there a safe dose? This is the question that researchers, hepatologists, and health institutions have sought to answer more precisely in recent decades. The idea here is to understand the risks of alcohol consumption. At another time, I'll research the possible benefits (are there any?). If we (humans) have been drinking for so long, there must be something, right?

1. Introduction: A Personal Discovery on YouTube

Hi! This is Ken. Today I want to share something a little different from the usual. As a curious and self-taught Japanese person, I'm always falling into YouTube traps—and one day I ended up watching an interview with a Japanese doctor about the damage alcohol causes to the liver.

That doctor is Takashi Nishiguchi, an authority in the field, former director of the Japan Society of Hepatology , and professor at Hyogo Medical University. He says something that has been echoing in my mind ever since:

“There is no alcohol that is safe for the liver.”

As someone who works with beverages (Quetzalli is my brand of natural ready-to-drink drinks), I was wondering. Not because I wanted to quit drinking—but because I believe we make better decisions when we're well-informed. So, I decided to write this article, combining what I've learned from my own relationship with alcohol.

2. My relationship with alcohol: in my time, at my pace

I've always been one of those people who prefers to drink slowly. I've never been one for "getting too crazy" or throwing back shots like it's a competition. For me, drinking is more about enjoying the moment —not about disconnecting from reality.

Wine and beer don't mix well with me. I get bloated, my head feels heavy, and sometimes I even get acid reflux. However, I can enjoy smooth spirits—especially those I make a point of using natural ingredients and fruit pulps at Quetzalli—without a problem.

Oh, and if there's one thing I've learned: always listen to your body. Just because something is socially acceptable doesn't mean it suits you.

3. Professor Nishiguchi's speech: alcohol as a real liver risk

Returning to the interview, Dr. Nishiguchi explains that he's increasingly seeing patients with alcoholic liver disease today, even without a classic history of alcoholism. People who have "just one can a day," or a glass of wine with dinner.

According to him:

"Acute alcoholic hepatitis is on the rise. And many of my cirrhosis patients consumed less than 40g of alcohol per day."
— Takashi Nishiguchi, 2023 – interview with Noukatsu Shimbun

For reference: 40g of pure alcohol is equivalent to approximately:

• 1 liter of beer (5%)

• 400 ml of wine (12%)

• 100 ml of distillate (40%)

In other words, even consumption considered “moderate” can cause cumulative damage to the liver over the years.

4. How does alcohol affect the liver?

The liver is responsible for metabolizing over 90% of the ethanol we consume. The process, in simplified terms, goes like this:

1. Ethanol is converted to acetaldehyde by the enzyme ADH (alcohol dehydrogenase) .

2. Acetaldehyde — highly toxic and carcinogenic — is converted to acetate by another enzyme, ALDH (aldehyde dehydrogenase) .

3. The acetate is then used as an energy source or eliminated.

The problem is that acetaldehyde can accumulate and cause cellular damage—especially in the liver, which is the first to receive this substance in high concentrations.

According to the International Agency for Research on Cancer (IARC) , acetaldehyde is classified as a Group 1 carcinogen , meaning it is definitely related to human cancer. [IARC Monographs, 2010]

5. Alcohol-related liver disease

Drinking regularly, even in small amounts, can cause the following conditions:

5.1. Hepatic steatosis (fatty liver)

It's the accumulation of fat in liver cells. It can be reversible, but it's the first stage of alcoholic liver disease.

5.2. Alcoholic hepatitis

It's inflammation of the liver caused by alcohol. It can be acute (with fever and pain) or chronic (silent for years). Symptoms appear when there's already significant inflammation.

5.3. Fibrosis and cirrhosis

Fibrosis is the formation of scar tissue in the liver. When it progresses, it becomes cirrhosis—an irreversible condition that compromises liver function and can lead to organ failure.

5.4. Liver cancer

Alcohol is directly linked to an increased risk of hepatocellular carcinoma, especially in people with cirrhosis. [World Health Organization, 2014]

6. But isn't red wine good for you?

This is an argument I hear a lot. For a long time, the so-called "French paradox"—the idea that French people drink wine regularly and have less heart disease—was used to justify moderate alcohol consumption.

But more recent studies, such as the Global Burden of Disease Study 2018 published in The Lancet , have shown that:

“The level of alcohol consumption that minimizes health risks is zero.”
— Lancet, 2018; GBD 2016 Alcohol Collaborators .

Even small amounts are associated with an increased risk of cancer, cirrhosis, cardiovascular disease, and other complications.

7. Alcohol and the risk of cancer

Few people know this, but alcohol is among the main preventable risk factors for cancer. The WHO lists alcohol as responsible for about 5% of all cancer cases worldwide .

The main types of cancer associated with alcohol are:

• Liver

• Mouth

• Pharynx

• Larynx

• Esophagus

• Breast

• Intestine

And the risk increases even with moderate doses —especially in the case of breast cancer in women. [WHO Fact Sheet on Alcohol and Cancer, 2022]

8. Is there a safe dose?

According to the World Health Organization (WHO), there is no completely safe level of consumption to prevent the effects of alcohol on health.

The US National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines the following parameters for "low risk":

• Men: up to 2 standard doses per day

• Women: up to 1 dose per day

But even this "low risk" doesn't equal zero risk. In Asian populations, for example, there is a genetic deficiency in the enzyme ALDH2, which increases acetaldehyde toxicity and the risk of liver damage and cancer. [Chen et al., Human Genomics , 2009]

9. What does the Japanese Liver Society say?

The日本肝臓学会 (Japan Society of Hepatology) guideline recommends:

• For men: less than 20g of pure alcohol per day

• For women: less than 10g per day

• Ideally, alcohol-free days interspersed throughout the week

And reinforces the importance of:

• Regular liver enzyme tests (GOT, GPT, GGT)

• Abdominal ultrasound

• Pay attention to symptoms such as fatigue, yellow eyes, loss of appetite

10. Listen to your body (and its limits)

If there's one thing I've learned—as both a consumer and a producer—it's that alcohol manifests itself differently in each person.

Some warning signs:

• Feeling tired the next day even with little drinking

• Swelling in the abdomen or legs

• Loss of appetite

• Recurrent nausea

• Mood swings or insomnia after drinking

This isn't always "normal." It's often a sign that your body is overworked .

11. Is conscious consumption possible?

Yes. The point here is not to demonize alcohol , but to recognize that it is not harmless — and that it deserves respect.

Some practices that I follow and recommend:

• Avoid drinking every day

• Prioritize drinks with natural ingredients and fewer additives

• Drink water between drinks

• Eat before or during consumption

• Do not mix with medications (especially paracetamol)

• Respect your rhythm (the famous “alcoholic rhythm”)

• Don't feel obligated to drink to please others.

12. Conclusion: more awareness, less (health) hangover

When I saw that video of the Japanese doctor, I confess I didn't expect it to have such an impact. But it was then that I realized how much we normalize certain habits without understanding the underlying reasons.

The liver is a silent hero. It works tirelessly to process what we eat, drink, and breathe. And it almost never complains. But when it speaks, it's usually too late.

That's why I decided to bring up this topic. Because the more we understand, the more freedom we have to make informed choices.

13. Sources consulted

• Noukatsu Shimbun. “アルコールは肝臓にとって安全な量は存在しない”. 2023. https://noukatsu-shimbun.jp/2023/10/13/14068/

• The Japan Society of Hepatology. Guideline 2020.

• World Health Organization (WHO). Fact Sheet – Alcohol. https://www.who.int/news-room/fact-sheets/detail/alcohol

• The Lancet. GBD 2016 Alcohol Collaborators. 2018.

• International Agency for Research on Cancer (IARC). Monographs on the Evaluation of Carcinogenic Risks to Humans. 2010.

• National Institute on Alcohol Abuse and Alcoholism (NIAAA). Drinking Levels Defined. https://www.niaaa.nih.gov

• Chen CH et al., Human Genomics , 2009. “ALDH2 deficiency and alcohol-related disease risk in Asians.”