Grass-fed butter is the healthiest butter you can buy. It delivers more beneficial fats, more fat-soluble vitamins, and a better overall nutrient profile than conventional butter. But the full answer depends on what you’re comparing: regular vs. grass-fed, salted vs. unsalted, dairy vs. plant-based. A single tablespoon of any butter contains about 102 calories and 11.5 grams of fat, so the real differences come down to the quality of that fat and what else comes along with it.
Why Grass-Fed Butter Comes Out on Top
The diet of the cow changes the nutritional makeup of the butter. Grass-fed butter contains about 26% more omega-3 fatty acids than butter from grain-fed cows. Even more striking, grass-fed dairy can contain up to 500% more conjugated linoleic acid (CLA), a naturally occurring fat linked to reduced inflammation and improved body composition in some studies. In one experiment, cows raised on pasture produced milk with five times the CLA of cows eating a corn-based diet.
Grass-fed butter is also one of the richest dietary sources of vitamin K2, specifically the MK-4 form, which plays a role in directing calcium into bones and teeth rather than arteries. Lab analyses of butter samples have found MK-4 concentrations ranging roughly from 84 to 197 nanograms per gram, with grass-fed varieties tending toward the higher end. You’d need to eat a lot of butter to get a therapeutic dose of K2 from this alone, but it contributes meaningfully as part of a broader diet.
Grass-fed butter also has a deeper yellow color, which reflects higher levels of beta-carotene, a precursor to vitamin A. If you see pale, white butter, the cows were likely grain-fed.
Salted vs. Unsalted Butter
If you’re watching sodium intake, unsalted butter is the better pick. A stick of salted butter (four tablespoons) contains between 600 and 900 milligrams of sodium depending on the brand. That’s a quarter to a half teaspoon of salt per stick. Unsalted butter contains only trace amounts of naturally occurring sodium, so little that manufacturers aren’t required to list it on the label.
Nutritionally, the two are otherwise identical. The salt doesn’t change the fat composition. It does extend shelf life slightly, so unsalted butter tends to be fresher when you buy it, since it has to move off the shelf faster.
Cultured Butter and Gut Health
Cultured butter is made by fermenting cream with lactic acid bacteria before churning. This gives it a tangy, complex flavor that many people prefer for cooking. The fermentation process produces flavor compounds like diacetyl and acetaldehyde, which are responsible for that distinctive richness.
Some beneficial bacteria do survive in cultured butter, but not in large enough numbers to treat it as a probiotic food. Research suggests cultured butter “may contribute to the uptake of beneficial metabolites” but should be considered a supplementary carrier, not a primary source of probiotics. If gut health is your goal, yogurt, kefir, or fermented vegetables will deliver far more live cultures per serving.
That said, all butter contains butyrate, a short-chain fatty acid that serves as the primary energy source for the cells lining your colon. Butter is actually the most concentrated dietary source of butyrate, providing up to 3 grams per 100 grams. Butyrate supports the intestinal barrier and has shown anti-inflammatory effects in animal studies, reducing several markers of inflammation. However, the most effective way to increase butyrate levels in your gut is by eating fiber-rich foods, which your gut bacteria ferment into butyrate on-site, right where it’s needed most.
How Plant-Based Butters Compare
Plant-based butters are made by blending water with oils like olive, avocado, coconut, or palm kernel oil. The healthiest versions use olive or avocado oil as the primary fat, since these are rich in monounsaturated fats, the same type found in nuts and fatty fish that support heart health. These spreads tend to be higher in monounsaturated fat and lower in saturated fat than dairy butter.
Not all plant butters are equal, though. Products built around coconut or palm kernel oil can contain just as much saturated fat as dairy butter, sometimes more. Check the ingredient list: if coconut or palm oil appears first, you’re not getting much of an advantage over regular butter. The best plant-based options list olive oil or avocado oil as the first ingredient and keep the saturated fat per serving under 3 or 4 grams.
Plant butters won’t give you CLA, vitamin K2, or butyrate. They fill a different niche, mainly for people avoiding dairy or trying to shift their fat profile toward unsaturated sources.
What About Margarine?
Margarine’s reputation took a hit decades ago because of trans fats, which are strongly linked to heart disease. In the U.S., added trans fats are no longer allowed in margarine. Modern soft margarines sold in tubs are generally lower in saturated fat than butter and can be a reasonable option, particularly those made with olive or canola oil. Margarine sold outside the United States may still contain trans fats, so checking labels matters if you’re buying imported brands.
How Much Butter Is Too Much
The American Heart Association’s 2026 dietary guidance recommends keeping saturated fat below 10% of total daily calories. On a 2,000-calorie diet, that works out to about 22 grams. One tablespoon of butter contains roughly 7 grams of saturated fat, so a single tablespoon already accounts for about a third of that limit. If butter is your main source of saturated fat, two tablespoons a day leaves room for other foods. If you’re also eating cheese, red meat, or full-fat dairy, you’ll hit that ceiling quickly.
The type of butter you choose matters less than the total amount. Grass-fed butter is nutritionally superior, but it still contains the same amount of saturated fat per serving as conventional butter. The extra omega-3s and CLA don’t cancel that out. Use butter deliberately, as a flavor tool, rather than as a default cooking fat for everything. Olive oil remains a better everyday option for sautéing and roasting.
The Bottom Line on Choosing Butter
If you’re buying dairy butter, go with grass-fed and unsalted. You’ll get a meaningfully better nutrient profile, especially more omega-3s, CLA, and vitamin K2, without the added sodium. Look for a deep yellow color and “grass-fed” or “pasture-raised” on the label. Kerrygold, Vital Farms, and Organic Valley Pasture-Raised are widely available options. If you’re avoiding dairy, choose a plant-based butter built on olive or avocado oil rather than coconut or palm. And regardless of type, keep portions moderate: butter is a nutrient-dense fat, not a health food you can eat without limits.