🫀Saturated fats from dairy foods: Friend of foe to heart health?

A plethora of research shows that dairy foods have no effect on the risk of cardiovascular disease, with some studies even showing a protective effect. This is despite dairy foods being rich in saturated fats, which are known to increase LDL-C ("bad" cholesterol).

Even replacing saturated fats from processed meat with saturated fats from milk reduces the risk of cardiovascular disease.

One hypothesis is that the combination of nutrients in dairy foods (e.g., calcium and concentration of fats) may have protective effects.

Calcium, for instance, is thought to bind with bile acids to form insoluble compounds, which are then excreted, resulting in lower fat absorption. This could result in greater clearance of cholesterol from the blood as the liver replaces lost bile acids, leading to reduced LDL-C concentration in the blood.

Indeed, consuming the same amount of calories and saturated fats from cheese or milk results in lower levels of LDL-C when compared to butter.

And finally, eating melted cheese has been shown to increase total cholesterol by 0.20 mmol/L (quite significant) when compared to eating unmelted cheese, highlighting the importance of food structure.

🥊 Punchline

Focusing solely on the saturated fat content of dairy can be shortsighted. Dairy foods offer much more, and their composition is believed to provide protective effects against cardiovascular disease despite the high saturated fat content.

💪 Why protein content alone isn’t enough: The role of whole dairy food to muscle growth

Proteins are important for stimulating protein synthesis and muscle growth, but they aren't the only factor.

Other nutritional elements also play a role, primarily the interactions between nutrients and the physical structure of food.

For example, in a study, drinking whole milk stimulated greater availability of amino acids in the blood compared to skimmed milk, even after matching both drinks by calorie and protein content. It is hypothesized that the interactions between nutrients (protein and fats) were behind the greater spike in amino acid utilization in whole milk.

Similarly, whole eggs stimulate greater muscle synthesis compared to egg whites. This is likely due to the interaction of protein with other components of the yolk, such as cholesterol, minerals, and other bioactive elements, which can facilitate the uptake of amino acids in muscle tissue.

When comparing whole foods, skimmed milk stimulated greater protein synthesis two hours after the meal than beef, despite both portion sizes having the same protein content.

This highlights that other components of milk beyond protein digestion and amino acids modulated the postprandial response of muscle protein synthesis.

🥊 Punchline

Protein content alone is not everything. Whole foods offer benefits beyond protein content alone, such as the interaction between nutrients, which are known to stimulate greater muscle protein synthesis than each respective nutrient in isolation or the sum of their constituent parts.

🥛 Is whole diary more important than leucine content for muscle growth?

The rate of digestion and amino acid composition are key nutritional factors that determine the muscle growth potential of a protein source.

Or so it was thought.

Leucine is considered a key amino acid for muscle growth. Indeed, drinking whey protein, which is fast absorbed and leucine-rich, stimulates greater muscle growth in the period after drinking it compared to casein protein, which is slowly digested and has a lower leucine content.

However, recent studies have challenged the leucine trigger hypothesis:

• Drinking 20g of milk protein or whey protein resulted in the same muscle protein synthesis in middle-aged men, despite the greater digestion rate and leucine content of whey.

• Drinking casein protein or casein + milk fats resulted in the same muscle protein synthesis in older men, despite the greater absorption rate of casein alone.

The leucine hypothesis - higher leucine content stimulates greater muscle growth - is less relevant when consuming whole foods.

Instead, other nutritional components (i.e., nutrient interactions, vitamins, minerals) and the food structure of dairy foods have been proposed to modulate muscle protein synthesis via distinct mechanisms.

🥊 Punchline

The leucine content may be relevant when consuming protein drinks, but is less relevant when consuming whole dairy foods, as other nutritional components and the food structure can have distinct effect on muscle protein synthesis.