Bone marrow is a nutrient-dense food that provides significant amounts of vitamin B12, iron, and healthy fats. A single tablespoon (about 14 grams) contains roughly 110 calories, nearly all of them from fat, so it packs a lot of nutrition into a small amount. Whether it’s “good for you” depends on how much you eat and what your diet looks like overall.
What’s Actually in Bone Marrow
Bone marrow is primarily fat. Per 100 grams of raw marrow, you’re looking at about 785 calories and 84 grams of fat, with only around 7 grams of protein. That makes it one of the most calorie-dense whole foods you can eat. In realistic serving sizes (a tablespoon scraped from a roasted bone), the numbers are more modest: 110 calories, 12 grams of fat, and 1 gram of protein.
The micronutrient profile is where marrow stands out. A 100-gram portion of reindeer bone marrow delivers 52% of the daily value for vitamin B12, 39% for riboflavin (vitamin B2), and 17% for iron. Even a tablespoon-sized serving contributes meaningful amounts of B12, a vitamin that many people, especially older adults and those on plant-based diets, struggle to get enough of.
The Fat in Bone Marrow Is Mostly Unsaturated
Despite its richness, bone marrow fat isn’t the artery-clogging profile many people assume. Research on farmed deer marrow found that monounsaturated fatty acids, the same type of fat praised in olive oil and avocados, made up roughly 55 to 59% of total fat. Saturated fat accounted for about 21 to 23%. The exact ratio shifts depending on what the animal ate (grass-fed animals tend to have slightly different profiles than grain-fed ones), but the overall pattern holds: bone marrow fat leans more toward the types associated with heart health than away from them.
Bone marrow from grass-fed animals also contains conjugated linoleic acid (CLA), a naturally occurring fat with anti-inflammatory properties. In animal studies, diets enriched with CLA from beef reduced markers of inflammation by lowering the production of inflammatory signaling molecules and increasing anti-inflammatory ones. The concentrations in a typical serving of marrow are modest, but they add to the overall quality of the fat you’re consuming.
Collagen and Joint-Supporting Compounds
Bone marrow and the connective tissue surrounding it contain collagen building blocks, specifically the amino acids glycine, proline, and hydroxyproline. These are the same compounds your body uses to build and repair cartilage, skin, and tendons. Beef bone broth, which extracts many of these compounds during cooking, contains about 3.7 milligrams of glycine and 2.2 milligrams of proline per gram of product.
Glycine plays a role in protein absorption and supports collagen structure throughout the body. Proline contributes to skin health and wound healing by stimulating new collagen production. That said, it’s worth being honest about the evidence: most health claims around bone broth and marrow’s collagen benefits haven’t been rigorously tested in human clinical trials. The amino acids are real and measurable, but whether eating marrow translates directly into better joints or younger-looking skin remains an open question. Your body breaks these amino acids down during digestion and reassembles them where needed, so the benefit is indirect rather than targeted.
Red Marrow vs. Yellow Marrow
Not all bone marrow is the same. The marrow you find in large leg bones at the butcher counter is yellow marrow, which is almost entirely fat. Its primary biological role is energy storage. Red marrow, found in flat bones like the pelvis and ribs, is the tissue responsible for producing blood cells. It’s richer in protein and iron but isn’t commonly sold or eaten in most culinary traditions.
When people talk about eating bone marrow, they’re almost always referring to yellow marrow from beef femur or shank bones. This is the soft, buttery substance you roast and spread on toast. It’s delicious and nutritious, but its benefits are mostly about healthy fats and fat-soluble nutrients rather than blood cell production.
How Much to Eat
Because bone marrow is so calorie-dense, portion size matters. A tablespoon or two scooped from a roasted bone (roughly the amount you’d get from one split marrow bone at a restaurant) is a reasonable serving. At that size, you’re getting valuable B12 and iron without an overwhelming calorie load.
If you’re eating marrow as an occasional addition to meals, perhaps roasted bones once or twice a week, it fits comfortably into most diets. Treating it like butter is a useful mental model: a little goes a long way, and it works best as a complement to vegetables, bread, or other foods rather than a main course. People watching their saturated fat intake should be mindful, but the favorable monounsaturated-to-saturated ratio makes marrow a better choice than many other animal fats.
Practical Ways to Get the Benefits
Roasting split marrow bones at high heat (about 450°F for 15 to 20 minutes) is the simplest preparation. The marrow softens into a spreadable, savory paste that you can eat on crusty bread with a pinch of salt. Bone broth is another option that extracts many of the same nutrients, especially collagen-related amino acids, into a drinkable form with far fewer calories per serving.
You can also ask your butcher to cut marrow bones into shorter segments (2 to 3 inches), which makes portioning easier and ensures the marrow cooks evenly. Grass-fed beef bones tend to have a slightly better fatty acid profile, but conventional bones still provide the same core nutrients. Frozen marrow bones are widely available and just as nutritious as fresh ones.