Cow's milk, grass-fed

What’s new and beneficial about grass-fed cow’s milk

• CLA (conjugated linoleic acid) is a type of fat associated with a wide variety of health benefits, including immune and inflammatory system support, improved bone mass, improved blood sugar regulation, reduced body fat, reduced risk of heart attack, and maintenance of lean body mass. According to recent studies, you’ll find yourself getting at least 75 milligrams of CLA from an 8-ounce serving of grass-fed cow’s milk. (In some cases, you may even get two to three times this amount. The amount of CLA in cow’s milk tends to increase along with consumption of fresh grasses by the cows, and when cows have had ample access to fresh pasture, you are likely to get increased amounts of CLA.) Since the CLA content of milk from 100% grass-fed cows is typically two to fives times greater than the CLA content of milk from conventionally fed cows, 100% grass-fed milk can provide you with increased health benefits in the areas described above.
• Improved intake of omega-3 fat is another health benefit that can be obtained from 100% grass-fed cow’s milk. The omega-3 fat content of grass-fed cow’s milk can vary widely, due to the wide variety of forage crops that can be planted in pastures (or that grow on pastureland in the wild). This omega-3 content also varies with the age, breed, and health of cows and seasonal plant cycles in pastureland. At the lower end of the spectrum, recent research shows 50-65 milligrams of omega-3s (in the form of alpha-linolenic acid, or ALA) in 8 ounces of grass-fed cow’s milk. At the higher end of the spectrum, those same 8 ounces may provide 120-150 milligrams of omega-3s. While these amounts of ALA are not large, they’re going to be helpful to many individuals who are deficient in omega-3s. The relatively low ratio of omega-6s to omega-3s in 100% grass-fed cow’s milk may also enhance the benefits that you get from these omega-3s. This ratio typically falls between 2:1 and 3:1—quite unlike the ratio in milk from traditionally fed cows, which often fall into the range of 8:1 or higher. Since omega-6 metabolism can interfere with omega-3 metabolism, the relatively reduced amounts of omega-6s in 100% grass-fed cow’s milk may help improve the metabolism of omega-3s in your body after you’ve consumed the milk.
• Based on recent research studies, the overall fat composition of 100% grass-fed milk is not what you might think. There are about 8 grams of total fat in 8 ounces of whole grass-fed cow’s milk. About 2 grams (or 25%) come from monounsaturated fat in the form of oleic acid. This omega-9 fatty acid is the primary fatty acid found in olive oil, and when it replaces other types of fat in the diet, it’s been linked to reduction in high blood pressure as well as reduction in high blood cholesterol levels. About 4.5 grams (or 56%) come from saturated fat - a type of fat that we often associate with unwanted health consequences. However, the type of saturated fat in 100% grass-fed cow’s milk does not fully fit the “unwanted” fat category. About 6-7% of this saturated fat is “short-chain” saturated fat and it can function as a “probiotic” that supports the health of friendly bacteria in the intestine. Nearly half of the saturated fat is “medium chain” saturated fat—the kind that is predominant in coconut oil. Medium chain saturated fat is more easily digested and metabolized in the body, and in some studies, it’s been associated with immune system benefits. Within the 4.5 grams of saturated fat in 8 ounces of 100% grass-fed whole milk, only 25-30% come from palmitic acid—a long chain fat that’s been more closely associated with heart disease risk than other saturated fats. When taken as a whole, the fat composition of 100% grass-fed whole cow’s milk is much more balanced in terms of health risks and benefits than many people assume.

Cow’s milk, grass-fed
4.00 oz
(122.00 grams)

Calories: 74
GI: low

NutrientDRI/DV

 vitamin B1223%

 iodine19%

 vitamin D16%

 vitamin B216%

 phosphorus15%

 calcium14%

 pantothenic acid9%

 biotin8%

 selenium8%

 protein8%

 vitamin A6%

Food Rating System Chart

• Health Benefits
• Description
• History
• How to Select and Store
• How to Enjoy
• Individual Concerns
• Nutritional Profile
• References

Health benefits

Broad-based nutrient support

When obtained from 100% grass-fed cows, whole milk contains a surprising diversity of both conventional and phytonutrients. In the conventional category, you’ll find milk to be a very good source of vitamin B2 (riboflavin), vitamin D, and vitamin B12. It’s also a very good source of the minerals iodine and phosphorus, and a good source of calcium. Our rating system also qualifies whole cow’s milk as a good source of protein.

As described previously, the fat composition of 100% grass-fed whole cow’s milk is not what you might think. In an 8-ounce serving, you’re likely to get at least 50-65 milligrams of omega-3s (in the form of alpha-linolenic acid, or ALA) and perhaps as much as 120-150 milligrams. You’re also going to get a relative low ratio of omega-6:omega-3 fat in the range of 2:1 to 3:1. That ratio is healthier than the 8:1 (or higher) ratio you’re likely to get from conventionally fed cows, and it’s also much healthier than the ratio currently consumed by the average U.S. adult. Included within the fat composition of 100% grass-fed whole milk is CLA (conjugated linoleic acid), a type of fat associated with immune, cardiovascular and other benefits.

In terms of phytonutrients, you’re likely to get 16-40 micrograms of beta-carotene in 8 ounces of 100% grass-fed whole cow’s milk, along with isoflavones like formononetin, biochanin A, and prunetin depending on the type of fresh pasture and silage consumed by the cows. You’re also like to get lignans like secoisolariciresinol and matairesinol, once again, depending on the cows’ diet. The chart below gives some simple examples of the relationship between a cow’s diet and phytonutrients in milk.

Type of Silage

Phytonutrients Found to Increase in the Cow’s Milk

red clover

formononetin (isoflavone)

alfalfa

biochanin A (isoflavone) and prunetin (isoflavone)

birdsfoot trefoil

secoisolariciresinol (lignan) and matairesinol (lignan)

Grass silage has also been shown to increase the beta-carotene content in grass-fed cow’s milk to levels of approximately 40 micrograms in 8 ounces. These levels are about 4 times higher than the amount of beta-carotene found in conventional cow’s milk.

Antioxidant support

Antioxidants found in 100% grass-fed whole milk can include the isoflavones formononetin, biochanin A, and prunetin. Antioxidant lignans can include secoisolariciresinol and matairesinol. Vitamin antioxidants include vitamin E (which is increased by about 50% in milk from 100% grass-fed cows versus conventionally fed cows) and mineral antioxidants include selenium and zinc. Grass feeding also increases the amount of another key antioxidant—beta-carotene—in cow’s milk. At approximately 40 micrograms per 8 ounces, this level is about 4 times higher than the level in milk from conventionally fed cows.

Other health benefits

There are preliminary studies on the health benefits of cow’s milk in a variety of areas. However, no large-scale studies have been done exclusively on 100% grass-fed whole milk. Most of the studies have been conducted using milk from conventionally fed cows on relatively small groups of participants. Within this context, there is some evidence of improved weight loss and improved fat loss when cow’s milk is incorporated into a closely monitored low-calorie diet.

There is also evidence of decreased risk of gout in both men and women when milk is consumed in relatively high amounts (averaging at least one cup per day, and often 2-4 cups). Researchers are not clear about the mechanism of action here, but continue to look at relationships between increased intake of cow’s milk and decreased levels of uric acid in the blood. (High levels of uric acid usually precede the occurrence of gout.)

While cow’s milk has been widely promoted as a source of calcium and good bone health, large-scale studies showing significantly improved bone health in adults who regularly consume cow’s milk are lacking. Several studies have found decreased risk of bone fracture in children and teens who regularly consume milk, and animal studies show reduced risk of osteoporosis following regular milk consumption. Some of the research on bone health and the natural nutrient composition of cow’s milk is complicated by widespread fortification of cow’s milk with vitamin D. (Vitamin D plays an important role in bone health, and the addition of vitamin D to cow’s milk during processing might account for improved bone health.)

Studies on the relationship between cow’s milk intake and cancer risk are inconsistent. Some show mild decreases in cancer risk (for example, breast cancer in one group of French women), while others show mild increases (for example, breast cancer in one group of Japanese women). Still others find no connection. No large-scale studies have examined the relationship between milk from 100% grass-fed cows and cancer of any type.

Some of this confusion might be related to the widespread presence of hormonal residues in cow’s milk from conventionally fed cows, which may have increased cancer risk. These hormonal residues can have two sources. First, hormones may have been injected into the cows or added to their feed in order to increase rate of growth or milk yield. But equally important may be higher levels of hormones produced by the cows themselves. Unlike milking practices adopted by ancient nomadic cultures that restricted milking to the early months of pregnancy (when hormonal levels in the pregnant cows were relatively low), modern dairy farms maintain pregnancy in dairy cows about 80% of the year and milk throughout pregnancy, even during months when hormonal levels are relatively high.

Description

Like their fellow mammals, female cows can produce milk through the process called lactation. (In fact, the very word “mammal” refers to this milk-producing process, since milk is produced by the mammary glands in female animals and mamma in Latin means “breast.”) While this distinction holds true for all female cows, not all female cows are considered dairy cows. In the commercial milk industry, dairy cows consist of very specialized breeds that can produce very large amounts of milk. Over 90% of dairy cows in the U.S. are black and white Holsteins. After Holsteins, the most common U.S. dairy cows are Jerseys. Other dairy breeds include Ayrshires, Brown Swiss, and Guernseys.

Around two years of age, female dairy cows typically have their first calf, and along with calving, they begin to produce milk (lactation). Through a combination of steps (usually including artificial insemination to re-initiate pregnancy following the end of the first lactation cycle), dairy cows can be managed in such a way as to produce milk about 80% of the year for a period of 6-10 years. Specialized milking breeds like the ones described above average about 20,000 pounds of milk per year in the U.S., with some cows producing up to 37,500 pounds.

All cows belong to the Bovidae family of cloven-hooved, ruminant animals that includes bison, buffalo, sheep, goats, antelopes, gazelles, and muskoxen. Most also belong to the Bos Taurus genus and species in this animal family.

History

Many animals—including cows—have been milked for the purpose of providing humans with food for thousands of years. However, cows were not native to North America and did not arrive in what is now the United States until the 15th century AD when the Spanish brought them on ships from Europe. Over the next three and one-half centuries, most of the cows present in the U.S. belonged to families on family farms. It was not until the 1900’s that the dairy industry as we know it today began to develop, following invention of the pasteurization process and other events (such as the capacity to test dairy herds for the infectious disease tuberculosis).

Today there are approximately nine million dairy cows in the U.S., with five states (California, Wisconsin, New York, Pennsylvania, and Idaho) accounting for most of U.S. dairy production. This total number of dairy cows is about 25% lower than the number of dairy cows in the 1970’s. However, even though the total number of dairy cows has decreased, the total volume of milk from these cows has nearly doubled to an average level of about 20,000 pounds per year. In the U.S. the average dairy herd size is approximately 100 cows—translating into about 90,000 dairy farms in all U.S. states combined.

How to select and store

When purchasing milk, always use the “sell-by” date as a guide to the shelf life of the milk. Smell the top of the container to make sure that the milk doesn’t smell of spoilage that could have been caused by being stored for a period of time outside of the refrigerator. Select milk from the coldest part of the refrigerator case, which are usually the lower sections.

Milk should always be refrigerated since higher temperatures can cause it to turn sour rather quickly. Always seal or close the milk container when storing it to prevent the milk from absorbing the aromas of other foods in the refrigerator. Avoid storing milk on the refrigerator door since this exposes it to too much heat each time the refrigerator is opened and closed.

How to enjoy

A Few Quick Serving Ideas:

• Blend together milk, a banana and your other favorite fruits for a delicious shake.
• Add milk, raisins, cinnamon and nutmeg to a pot of cooked brown rice to make rice pudding.
• Make hot chocolate by combining milk, unsweetened dark chocolate and honey in a saucepan over low heat. Stir frequently.
• Splash some milk over your morning bowl of hot cereal.

For recipe ideas, see Recipes.

Individual concerns

Milk and adverse reactions

Milk is among the eight food types considered to be major food allergens in the U.S., requiring identification on food labels. Some people also have an intolerance to milk owing to the lactose sugar that it contains. For helpful information about this topic, please see our article, An Overview of Adverse Food Reactions.

Nutritional profile

Four oz (122g) at 74 calories provides tryptophan (28.1% DV), vitamin B12 (23% DV), iodine (19% DV), vitamin B2 (16% DV), vitamin D (16% DV), phosphorus (15% DV), calcium (14% DV). Smaller but measurable amounts of pantothenic acid (9% DV), selenium (8% DV), biotin (8% DV), protein (8% DV), vitamin A (6% DV) round out the profile. Depending on the composition of pasture forage, grass-fed milk can be a valuable source of phytonutrients including the isoflavones formononetin, biochanin A and prunetin as well as the lignans secoisolariciresinol and matairesinol. Grass-fed milk also provides beta-carotene and vitamin E in greater amounts than are present in milk from conventionally fed cows. Conjugated linoleic acid (CLA) is also provided in substantial amounts in milk from 100% grass-fed cows.