Increasing water intake is often recommended as part of a heart-healthy lifestyle. Proponents claim that drinking more water, especially before meals, can help reduce cholesterol levels and improve heart health. But what does the research say? Here, we’ll explore the evidence on whether drinking more water can lower cholesterol.
What is cholesterol?
Cholesterol is a waxy, fat-like substance found in all of the cells in your body. Your body needs cholesterol to build cell membranes, make hormones like estrogen and testosterone, and produce compounds that help you digest food. The liver produces all the cholesterol your body needs.
There are two main types of cholesterol:
- LDL cholesterol: Also called “bad” cholesterol, LDL cholesterol builds up on artery walls and increases your risk of heart attack and stroke.
- HDL cholesterol: Known as “good” cholesterol, HDL cholesterol ferries cholesterol from other parts of your body back to your liver for reprocessing or excretion. Higher HDL levels are associated with a lower risk of heart disease.
When you get your cholesterol tested, you’ll receive a breakdown of your total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides (a type of fat in your blood).
What causes high cholesterol?
A variety of factors can cause high cholesterol levels, including:
- Diet: Eating foods high in saturated and trans fats can raise cholesterol levels. These foods include red meat, full-fat dairy, fried foods, and baked goods.
- Weight: Being overweight or obese increases LDL cholesterol levels.
- Physical activity: Lack of exercise can lead to elevated cholesterol levels.
- Genetics: Some people inherit genes from their parents that cause high cholesterol.
- Smoking: Chemicals from cigarette smoke lower HDL cholesterol and raise LDL cholesterol.
- Diabetes: High blood sugar levels increase your risk for high cholesterol.
- Medications: Some drugs, like birth control pills and corticosteroids, can raise cholesterol.
Why is high cholesterol concerning?
Over time, high LDL cholesterol can cause a buildup of plaque on your artery walls. This buildup is known as atherosclerosis. Plaque narrows your arteries and makes them less flexible. It also increases the risk that a blood clot will form and block an artery.
Blockages caused by atherosclerosis can lead to dangerous health problems like:
- Heart attack: A blocked artery prevents oxygen-rich blood from reaching a portion of the heart.
- Stroke: Blocked blood flow to part of the brain cuts off vital oxygen and nutrients.
- Peripheral artery disease: Plaque buildup narrows arteries carrying blood to the legs and feet.
High cholesterol affects tens of millions of adults in the U.S. The Centers for Disease Control and Prevention (CDC) reports that nearly 94 million American adults (about 47%) have total cholesterol levels higher than the recommended range.
How could drinking more water help lower cholesterol?
Here are some proposed ways that increasing water consumption may potentially lower cholesterol levels:
- Suppressing appetite: Some research indicates that drinking water before meals can temporarily make you feel fuller, leading you to eat less. Eating less, particularly of foods high in saturated fats, may in turn help reduce cholesterol levels.
- Supporting metabolism: Staying well hydrated ensures your metabolism is working efficiently. Some hypothesize this may help burn more calories and fat, including cholesterol.
- Flushing fat: Drinking adequate water keeps things moving through your digestive system. Proponents argue this may help flush fat and cholesterol out before it can be absorbed.
- Thinning blood: Blood thickens when dehydrated. Some believe thinner blood may circulate more easily through arteries and help prevent plaque buildup.
However, these potential mechanisms are speculative. More research is needed to understand if and how increasing water intake could directly lower cholesterol.
What does the research say?
Only a handful of studies have looked specifically at the effects of drinking more water on cholesterol levels. Here is some of the current research:
- In a small 2003 study, 48 adults with high cholesterol were randomly assigned to drink 1.5 liters of water daily or maintain their usual water intake. After 6 weeks, the water group had significant reductions in total cholesterol and LDL cholesterol compared to the control group.
- A 2011 study had a similar design but included only 20 participants with high cholesterol. After 8 weeks, there were no significant differences in cholesterol levels between the high water intake group and control group.
- Researchers in 2017 looked at NHANES data for over 12,000 U.S. adults ages 18 and older. They found that those who drank more plain water generally had lower cholesterol levels.
- Another 2017 study analyzed data from over 18,000 Korean adults. Higher plain water intake was associated with a lower prevalence of high LDL cholesterol levels.
Overall, this preliminary research suggests a link between higher water consumption and improved cholesterol levels. However, the studies have significant limitations:
- The trials were small and short-term.
- They relied on self-reported dietary intake data.
- The observational studies do not prove cause and effect.
- Most did not account for potential confounding factors like diet quality.
More rigorous clinical trials are needed to determine if increasing water intake can directly and independently lower cholesterol in a meaningful way.
Water intake recommendations
Here are the general daily total water intake recommendations from health organizations:
| Group | Recommended Total Water Intake (from food and beverages) |
|---|---|
| Men | 3.7 liters (125 ounces) |
| Women | 2.7 liters (91 ounces) |
As a proportion of total intake, plain water should provide around 80% of daily fluid intake, or about 9-13 eight ounce cups.
Of course, water needs can vary based on your health, medication use, activity levels, and climate. It’s always best to drink water to satisfy your thirst.
Tips for increasing water intake
If you want to bump up your daily water consumption, here are some easy tips:
- Carry a water bottle with you throughout the day for easy sipping access.
- Choose water with meals instead of sugary drinks.
- Add a wedge of lemon, lime, or cucumber to your water for a flavor boost.
- Set a daily alarm on your phone to remind you to drink water at regular intervals.
- Download a water tracking app to help you meet daily goals.
- Opt for water when dining out instead of juice, soda, or alcohol.
- Replace your morning coffee or tea with a glass of hot water and lemon.
- Sparkling water can help make plain water more exciting to drink.
Start slow by adding 1-2 more cups per day and work your way up to meet fluid needs based on your health and activity levels.
The bottom line
Current research on the effects of water intake on cholesterol is limited and mixed. While some studies suggest higher water consumption may help lower cholesterol, more rigorous clinical trials are needed.
Increasing plain water intake may potentially help reduce cholesterol levels by suppressing appetite, supporting metabolism, flushing fat, and thinning blood. However, these proposed mechanisms need further study.
Drinking more water may be beneficial as part of an overall heart-healthy lifestyle. But other diet and lifestyle changes likely play a greater direct role in lowering high cholesterol.
Focus first on reducing saturated and trans fats, exercising regularly, losing excess weight, and managing conditions like diabetes. Speak to your doctor about options like medication or nutritional supplements if lifestyle changes alone don’t lower your cholesterol enough.
Drinking enough fluids daily is important for overall health. But evidence that specifically increasing water intake significantly lowers cholesterol is currently limited. More research is needed to make definitive recommendations.