A single cup of cow’s milk delivers a surprisingly broad range of nutrients, packing meaningful amounts of at least 9 vitamins and minerals. It’s one of the most nutrient-dense beverages available, which is why it remains a dietary staple for so many people. Here’s exactly what you’re getting in each glass.
The Major Minerals
Calcium is the nutrient most people associate with milk, and for good reason. One 8-ounce cup of whole milk contains about 276 mg of calcium. The current daily value for calcium is 1,300 mg, so a single glass covers roughly 21% of your daily needs. Your body also absorbs calcium from milk more consistently than from many plant-based sources, though some fortified alternatives like soy milk come close.
Milk is also a significant source of potassium and phosphorus, two minerals that tend to fly under the radar. A cup of low-fat milk provides about 366 mg of potassium and 232 mg of phosphorus. Potassium helps regulate blood pressure and fluid balance, while phosphorus works alongside calcium to maintain bone and tooth structure. You’ll also get around 27 mg of magnesium per cup, a mineral involved in muscle function, nerve signaling, and hundreds of enzymatic reactions throughout the body.
B Vitamins: Riboflavin and Beyond
Milk is one of the richest everyday sources of riboflavin (vitamin B2). Your body uses riboflavin to convert food into energy and to maintain healthy skin and eyes. The daily value for riboflavin is 1.3 mg, and a cup of milk contributes a substantial portion of that. Riboflavin is water-soluble, so it stays present in milk regardless of fat content.
Beyond riboflavin, milk contains several other B vitamins. Vitamin B12, which is essential for nerve function and red blood cell production, is naturally present in dairy. Pantothenic acid (B5) also appears in meaningful amounts, and its concentration in mature milk is actually higher than in the colostrum produced right after a cow gives birth. You’ll get smaller amounts of thiamine (B1) and niacin (B3) as well. Together, these B vitamins support your metabolism and energy levels throughout the day.
Vitamin D: Added, Not Natural
Vitamin D doesn’t occur naturally in milk in significant quantities. Nearly all commercial milk sold in the United States is voluntarily fortified with it. The FDA allows manufacturers to add up to 84 IU of vitamin D3 per 100 grams of milk. For a standard 8-ounce glass, that translates to roughly 100 to 120 IU, depending on the brand. While that’s not enough to meet your full daily needs (the daily value is 800 IU), it adds up quickly if you drink milk regularly or eat other dairy products.
Vitamin D helps your body absorb the calcium that milk naturally provides, which is why the two are so often paired through fortification. Without adequate vitamin D, even a calcium-rich diet won’t fully protect your bones.
Vitamin A Changes With Fat Content
Vitamin A is a fat-soluble vitamin, which means it naturally rides along with the fat in whole milk. When manufacturers remove fat to produce 2%, 1%, or skim milk, vitamin A gets stripped out in the process. To compensate, federal standards require that reduced-fat, low-fat, and fat-free milk be fortified with at least 2,000 IU of vitamin A per quart. Whole milk doesn’t carry this requirement because it retains enough vitamin A on its own.
This means the vitamin A content across different milk types is roughly comparable on the shelf, but the source differs. In whole milk, it’s naturally present. In lower-fat versions, it’s been added back in. Either way, vitamin A supports vision, immune function, and cell growth.
Iodine: A Hidden Strength
One of milk’s most underappreciated nutrients is iodine, a trace mineral your thyroid gland needs to produce hormones that regulate metabolism. According to USDA data, a cup of whole milk contains about 82 mcg of iodine. Skim milk is nearly identical at 84 mcg, and low-fat (1%) milk comes in at 88 mcg. The daily value for iodine is 150 mcg, so one glass of milk gets you more than halfway there.
Many people don’t realize how few foods are reliable iodine sources. Seafood and iodized salt are the other major ones. For people who eat limited seafood or use non-iodized salts like sea salt or Himalayan pink salt, dairy milk can be an important safeguard against iodine deficiency.
Protein and Other Nutrients
While not a vitamin or mineral, milk’s protein content (about 8 grams per cup) enhances the overall nutritional package. Milk protein contains all nine essential amino acids, making it a complete protein. It also contains small amounts of zinc, which supports immune function, and sodium (around 107 mg per cup of low-fat milk).
How Fat Content Affects the Nutrient Profile
Switching between whole, 2%, 1%, and skim milk changes calorie and fat intake but leaves most vitamins and minerals largely intact. Water-soluble nutrients like B vitamins, potassium, phosphorus, and iodine remain consistent across fat levels. The main nutritional shifts happen with fat-soluble vitamins A and D, both of which are added back through fortification in reduced-fat versions. Calcium and protein stay essentially the same whether you choose whole or skim. So the choice between fat levels is primarily about calories and dietary fat preference, not about missing out on key micronutrients.