The Heart-Health Benefits of Milk Protein, According to Science

Heart disease is a leading cause of death worldwide, and in the United States alone, it accounted for one in every three deaths in 2023. That’s a striking stat, especially since most cardiovascular disease is preventable through a lifestyle that includes regular exercise, consistent sleep, low stress, and a balanced diet. But recent research published in Nutrition Reviews found that one nutrient in particular may support a strong heart in more ways than one: milk protein.

The systematic review and meta-analysis examined multiple controlled studies and found that consuming 30 to 60 grams of milk protein per day was associated with modest yet meaningful improvements in cholesterol, triglycerides, and systolic blood pressure in adults. Among the data analyzed, total cholesterol decreased by about 4 mg/dL, triglycerides by 6 mg/dL, and systolic blood pressure by 2 mmHg compared to controls.

“This study is notable because cholesterol, triglycerides, and systolic blood pressure are three markers that collectively shape cardiovascular risk,” says Samantha Peterson, RD, a registered dietitian and cofounder of Simply Wellness. “More specifically, this research adds to a growing body of evidence showing that the type and quality of protein we eat can have measurable effects on cardiometabolic health, and it’s not just about total protein intake.” 

What are milk proteins, exactly?

Milk naturally contains two types of protein: casein (about 80%) and whey (about 20%), says Peterson.

“You can think of casein as the slow-and-steady type because it digests more gradually and provides a steady release of amino acids, while whey is the quick absorber, delivering a faster burst of protein to your muscles and cells,” she says.

Casein and whey are considered complete proteins, meaning they contain all nine essential amino acids your body needs but can’t make on its own. As a result, Peterson says these milk proteins are incredibly efficient at building and repairing tissues, supporting metabolism, and keeping you full and energized.

Milk proteins are found in cow’s milk and other dairy products such as cheese, yogurt, skyr, and kefir, as well as in protein isolates and powders, says Nishant Kalra, MD, an interventional cardiologist and regional chief medical officer at VitalSolution.

How do milk proteins reduce cholesterol, triglycerides, and blood pressure?

Milk proteins reduce cholesterol, triglycerides, and blood pressure through the following biological pathways, according to Peterson.

• They help your liver clear out extra cholesterol. When milk proteins are digested, they release small compounds called peptides that signal the liver to remove more LDL cholesterol (often called “bad” cholesterol) from the blood, helping keep total cholesterol levels in check.
• They improve how your body handles sugar and fat. By enhancing insulin sensitivity (the body’s ability to use the hormone insulin effectively), milk proteins help your body use glucose and fats more efficiently instead of storing them, which can lead to lower triglycerides over time.
• They support lean muscle and satiety. Because protein keeps you fuller for longer and helps preserve muscle, it can naturally lead to better body composition, a key factor in supporting healthy cholesterol and triglyceride levels.
• They relax your blood vessels. When milk proteins are broken down during digestion, they release tiny compounds called bioactive peptides. These compounds then act as natural blood pressure–lowering agents by helping your blood vessels relax and widen, allowing blood to flow more easily. This gentle “relaxing” effect helps reduce systolic blood pressure over time.

These mechanisms are beneficial in and of themselves, but the real magic happens when they work hand in hand. “Rather than three separate benefits, these are really different expressions of the same underlying shift: a more balanced metabolism and healthier blood vessel function,” says Peterson. “When your body’s metabolic ‘engine’ runs more efficiently, your heart, circulation, and lipid levels all benefit together.”

How much milk protein is necessary to reap the cardiovascular benefits? 

According to the study, consuming 30 to 60 grams of milk protein per day lowers cholesterol, triglycerides, and blood pressure. This “sweet spot” may sound technical, but 30 to 60 grams of milk protein daily is actually quite achievable through normal eating habits, Peterson says. “In everyday terms, that’s roughly two to four servings of high-protein dairy foods.”

For example, that could look like:

• A cup of Greek yogurt at breakfast (15 to 20 grams)
• A whey protein smoothie or shake after a workout (20 to 25 grams)
• A serving of cottage cheese or skyr as a snack or with fruit (15 to 20 grams)

There’s no need to overconsume milk protein, as it can cause stomach upset. However, research suggests that 1.6 to 2 grams of total protein per kilogram of body weight (roughly 110 to 140 grams daily for someone weighing 150 pounds) is typically well tolerated. For milk proteins specifically, moderation and variety are key.

“Having a few servings of dairy or milk protein–based foods daily fits comfortably within a balanced eating pattern, but if milk protein powders or shakes start to replace whole meals or crowd out produce, healthy fats, and fiber, that’s when you may lose some of the heart and gut benefits that come from dietary balance,” Peterson says.

If you experience digestive discomfort, the type of milk protein may matter. “Traditional cow milk contains both A1 and A2 beta-casein proteins, and for some people, A1 can be harder to digest, so choosing A2 milk or dairy products made only with A2 protein can be gentler on the gut while still providing all the benefits,” Peterson explains. That said, those with dairy allergies or kidney conditions should avoid dairy products and milk proteins unless directed by a doctor, Kalra adds.

How milk protein compares to other protein sources 

Plant proteins, such as those from beans, lentils, and nuts, are praised for supporting heart health, largely thanks to their fiber and antioxidant content. But milk proteins bring something different to the table because they contain a uniquely rich mix of amino acids and bioactive peptides that interact directly with blood vessels and cholesterol metabolism, Peterson says.

To get into the nitty-gritty, Peterson reiterates that peptides released from whey and casein during digestion help blood vessels relax (supporting healthy blood pressure) and encourage the liver to clear LDL cholesterol from circulation. 

Plant proteins shine in other ways — mainly through their fiber, phytonutrients, and polyphenols — but they don’t have quite the same peptide activity as whey and casein, she explains. 

With that in mind, the real heart health perks come from a combination of the two. “Think of milk proteins and plant proteins as teammates rather than rivals,” Peterson says. “Adding Greek yogurt to a berry-and-nut bowl, blending a whey protein smoothie with spinach and chia seeds, or enjoying cottage cheese alongside roasted vegetables delivers ‘food synergy,’ because the idea is that it’s not just one nutrient alone, but rather how everything works together in the body.”