A growing body of medical research is raising serious questions about the long accepted belief that moderate drinking is harmless.

For years, alcohol has been woven into American social life through celebrations, sporting events, dinners, and weekend gatherings. However, researchers now say the health risks connected to alcohol are far broader than many people realize.

Doctors and public health experts are increasingly warning that alcohol affects nearly every major system in the human body.

According to recent studies, alcohol has been directly linked to dozens of diseases, including liver disease, heart complications, pancreatitis, ulcers, and mental health disorders.

Here's What They're Not Telling You About Your Retirement

Researchers also say alcohol contributes to conditions such as cancer, dementia, diabetes, and stroke.

“Alcohol is inherently toxic. We use alcohol to disinfect; we use alcohol to kill organisms.

So, the question is, is any amount of it safe?” said Dr. Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver.

One of the more alarming findings centers on the immune system. Scientists say even one alcoholic drink can weaken the body’s natural defenses within minutes. White blood cells that normally attack viruses and bacteria become less effective after alcohol consumption.

This Could Be the Most Important Video Gun Owners Watch All Year

While occasional drinking may only create temporary effects, long term heavy drinking can cause deeper and sometimes lasting damage to the immune system.

Researchers are also paying close attention to binge drinking, which has become more common among adults beyond the college years. Medical experts warn that consuming several drinks in a short period can weaken immune response for an entire day.

At the same time, chronic alcohol abuse can permanently damage critical immune cells, leaving people more vulnerable to illnesses such as pneumonia and tuberculosis.

Cancer risks connected to alcohol have become another major concern. Former United States Surgeon General Dr. Vivek Murthy recently called for updated warning labels on alcoholic beverages because many Americans remain unaware of the connection between drinking and cancer.

According to health officials, alcohol is now considered the third leading preventable cause of cancer in the United States behind tobacco and obesity.

“Alcohol is a well-established, preventable cause of cancer responsible for about 100,000 cases of cancer and 20,000 cancer deaths annually in the United States — greater than the 13,500 alcohol-associated traffic crash fatalities per year in the US — yet the majority of Americans are unaware of this risk,” Murthy said in a statement.

Health officials say alcohol damages DNA and increases inflammation throughout the body. Because of that, experts believe every type of alcohol contributes to cancer risk. For women, breast cancer remains one of the most common alcohol related cancers.

For men, colorectal cancer is strongly associated with drinking. Scientists also note that quitting alcohol can significantly reduce future risk, especially if a person stops before permanent damage develops.

“Cancer takes years to develop. Therefore, you may already have cancer inside of you that was caused by alcohol, and you may still get cancer after stopping,” said Sinclair Carr, a doctoral student affiliated with the Institute for Health Metrics and Evaluation.

“However, if you do not have any cancer inside of you and you stop drinking, you eliminate the future of any alcohol-attributable cancer.”

Research involving the brain is also changing public understanding of alcohol’s effects. Scientists once believed alcohol simply killed brain cells. Today, many researchers say alcohol damages the connections between neurons, which can lead to brain shrinkage and impaired memory.

One large study found that consuming as few as three drinks per week increased dementia risk by 15 percent when compared to people who drank only one drink weekly.

“Imaging studies suggest that cerebral atrophy, the shrinking of brain tissue, may partially recover within weeks to months of stopping drinking, with measurable changes often beginning in the first few weeks,” Carr said. “Cognitive functions such as attention, executive function, and memory can also improve with abstinence.”

Heart health has long been one of the most debated areas surrounding alcohol. Some older studies suggested small amounts of alcohol could benefit the heart. However, newer research is challenging that belief.

Recent studies found that even one drink per day may increase blood pressure. Doctors also warn that alcohol sharply increases health risks for people already dealing with obesity, diabetes, or hypertension.

“I think there’s enough evidence now that drinking may be more harmful than beneficial,” Freeman said. “Most of the professional societies tell people not to start drinking, drink as little as possible if they do drink, or stop drinking altogether.”

While Americans will ultimately make their own decisions about alcohol consumption, the science is becoming more difficult to ignore. Many researchers now believe the cultural normalization of drinking has overshadowed the long term health consequences.

Therefore, public awareness about the risks of alcohol may continue growing as more studies emerge in the years ahead.