kris ulland

Your Nutrition Partner

Vitamin D plays a critical role in supporting the immune system. Low vitamin D levels have been associated with higher rates of many chronic diseases.

More than 40% of Americans have been found to have insufficient blood levels of vitamin D (between 20-30 ng/mL). An additional nearly 30% of Americans have even lower vitamin D levels (below 20 ng.mL). An optimal vitamin D level is 50-80ng.mL.

For the body to produce its own vitamin D, we need direct skin exposure to sunlight. Unfortunately, we spend most of our time indoors or covered up by clothes and sunscreen. And, spending more time in the sun raises the risk of skin cancer and accelerated skin aging. The amount of vitamin D your skin makes depends on many factors, including the time of day, season, latitude and your skin pigmentation. Depending on where you live and your lifestyle, vitamin D production might decrease or be completely absent during the winter months. Sunscreen, while important to prevent skin cancer, also can decrease vitamin D production.

Another way to get vitamin D is through the diet, but most foods contain only a small amount. Excluding fortified foods, mushrooms are the only good non-animal source of vitamin D.

Like humans, mushrooms can synthesize this vitamin when exposed to UV light. Mushrooms produce vitamin D2, whereas animals produce vitamin D3. Though vitamin D2 helps raise blood levels of vitamin D, it may not be as effective as vitamin D3.

Nonetheless, wild mushrooms are excellent sources of vitamin D2. In fact, some varieties have as much as 2,300 IU per 3.5-ounce serving – nearly three times the RDA. On the other hand, commercially grown mushrooms are often grown in the dark and contain very little D2. Most organically grown mushroom you can find in your local co-op are treated with ultraviolet (UV light).

Vitamin D supports immune health by helping:

  • Optimize immune function that protects us from infectious disease
  • Control overly aggressive inflammatory immune responses

When excessive levels of immune-system proteins called cytokines provoke attacks on healthy tissues, the result is called a “cytokine storm”.  This is a dangerous reaction that can lead to acute respiratory distress syndrome which is an often fatal complication in which fluid collects in the lungs. Mortality in COVID-19 patients has been linked to the presence of  “cytokine storms” induced by the virus. Excessive production of pro-inflammatory cytokines leads to acute respiratory distress syndrome (ARDS) and widespread tissue damage resulting in multi-organ failure and death. Targeting cytokines during the management of COVID-19 patients has improved survival rates and reduced mortality.

Viral respiratory tract infections, such as the flu, are more common during the winter months. One reason for this may be seasonal variations in our vitamin D levels. During the winter, we get less sun, leading to lower vitamin D production. Infections are more common and severe in those with vitamin D deficiency.

Vitamin D contributes to many functions that help shield the body from infections and lessen their severity. Maintaining adequate levels of vitamin D:

  • Interferes with the ability of viruses to replicate and produce more viruses
  • Helps support and repair healthy cellular linings in the body, including in the airways and lungs
  • Increases production of proteins that shield against bacteria and viruses, enhancing the ability of cells to protect themselves from infection
  • Improves the ability of immune cells to mount an effective attack against specific viruses
  • Helps prevent the immune system from going overboard and producing excessive pro-inflammatory compounds in the lungs

Meta-analyses of clinical trials have shown that oral vitamin D has a protective effect against respiratory tract infections.

Vitamin D is also important for building and maintaining healthy bones. That’s because your body can only absorb calcium, the primary component of bone, when vitamin D is present. Vitamin D also regulates many other cellular functions in your body. Its anti-inflammatory, antioxidant and neuroprotective properties support immune health, muscle function and brain cell activity.

Research on vitamin D use for specific conditions shows:

  • Cognitive health. Research shows that low levels of vitamin D in the blood are associated with cognitive decline.
  • Inherited bone disorders. Vitamin D supplements can be used to help treat inherited disorders resulting from an inability to absorb or process vitamin D, such as familial hypophosphatemia.
  • Multiple sclerosis. Research suggests that long-term vitamin D supplementation reduces the risk of multiple sclerosis.
  • Osteomalacia. Vitamin D supplements are used to treat adults with severe vitamin D deficiency, resulting in loss of bone mineral content, bone pain, muscle weakness and soft bones (osteomalacia).
  • Osteoporosis. Studies suggest that people who get enough vitamin D and calcium in their diets can slow bone mineral loss, help prevent osteoporosis and reduce bone fractures. Ask your doctor if you need a calcium and vitamin D supplement to prevent or treat osteoporosis.
  • Psoriasis. Applying vitamin D or a topical preparation that contains a vitamin D compound called calcipotriene to the skin can treat plaque-type psoriasis in some people.
  • Rickets. This rare condition develops in children with vitamin D deficiency. Supplementing with vitamin D can prevent and treat the problem.

There are no universal guidelines for frequently of vitamin D testing. Given the high prevalence of vitamin D deficiency and the strong association of low vitamin D levels with several health issues, annual testing and supplementation to achieve adequate blood levels is highly recommended.

The current recommendations suggest consuming 400-800 IU (10-20 mcg) of vitamin D per day. However, people who need more vitamin D can safely consume 1,000-4,000 IU (25-100 mcg) daily.

The proportion of Americans who are taking vitamin D supplements at amounts that exceed the recommended limit has risen dramatically in recent years – jumping 590 percent between 1999 and 2014, according to a University of Minnesota study published in the Journal of the American Medical Association (JAMA).

The study also found that more than 3 percent of adults in the United States currently take vitamin D supplements at doses that have been associated with serious health problems. Excess vitamin D can cause calcium to build up in the blood, leading to fatigue, nausea, constipation, headaches and other symptoms, and may cause, over time, the development of kidney stones. High levels of vitamin D have also been associated with a greater risk for certain cancers (particularly prostate and pancreatic cancers) and even early death.

The study’s findings underscore the ongoing confusion that many people have about vitamin D recommendations – confusion that has led millions of people to take the supplement unnecessarily and, in some cases, dangerously.

“One in five U.S. adults are consuming vitamin D supplements,” said Mary Rooney, the lead author of the study and a doctoral student at the U of M, in a phone interview with MinnPost. “That’s pretty notable.”

The only way to know if you need vitamin D supplementation is to have a yearly blood test.

Crimini Mushrooms

Mushrooms have been consumed for centuries as part of diets promoted in folklore and Eastern medicine practices, including Traditional Chinese Medicine. The ancient Egyptians considered mushrooms, such as cremini mushrooms, to be a food that promoted immortality and were fed to royals.

Cremini mushrooms are the slightly more mature version of the common white button mushroom. You might see them referred to as brown mushrooms, Italian mushrooms, or baby bella mushrooms, or portobellini mushrooms.

Cremini mushrooms are still considered immature. Like their white counterparts, they’re young, not fully developed. Mature criminis become portobello mushrooms.

As they age, not only does their color change, shifting from pale white to a medium cocoa brown color, but their flavor intensifies. In part, this is due to the fact that the white versions have a slightly higher water content when compared with creminis. As the water content drops, the flavor becomes more concentrated.

Also, as the mushroom develops, the flavor compounds in the mushroom also intensify, which is why creminis taste so much more mushroomy than white mushrooms. Likewise, portobellos, which are the fully mature form of the mushroom, have a still lower water content, giving them a more meaty texture as well as a deeper mushroom flavor.

Crimini mushrooms are a source of B vitamins, phosphorus, selenium, copper, and even some fiber and protein. Mushrooms are very low in fat and calories, sugar and carbs.

Mushrooms of all kinds help to prevent free radical damage, problems with bone loss, and potentially weight gain or various types of cancer. In fact, mushrooms are associated with so many health-promoting effects that they’ve even earned their own research journal: the International Journal of Medicinal Mushrooms.

According to a 2012 report published in the journal 3Biotech regarding mushrooms’ ability to fight disease, researchers stated, “The chief medicinal uses of mushrooms discovered so far are as anti-oxidant, anti-diabetic, hypocholesterolemic, anti-tumor, anti-cancer, immunomodulatory, anti-allergic, nephroprotective, and anti-microbial agents.”

Some of the greatest benefits of cremini mushrooms are due to a little known amino acid called ergothioneine, which also works similarly to antioxidants. Another surprising attribute of mushrooms is that they provide a range of amino acids, the building blocks of proteins, especially glutamate. Cremini mushrooms also contain the phytochemical called conjugated linoleic acid, which research suggests has anticancer properties, in addition to offering protection against atherosclerosis or hardening of the arteries, high blood pressure, high cholesterol, diabetes and other conditions.

Only a very small number of foods actually provide vitamin D. While mushrooms typically only contain very low amounts of vitamin D, they’re unique in their ability to produce and provide much more when exposed to sunlight. Many adults and children are deficient in vitamin D due to spending most of their time indoors, which interferes with the body’s ability to make enough on its own.  When mushrooms are exposed to UV light for several hours they may be able to provide 100 percent of the recommended daily intake of vitamin D, offering benefits for bone health, immunity, mental health and more.

One cup of sliced, raw cremini mushrooms contains about: 

  • 19.4 calories
  • 3 grams carbohydrates
  • 1.8 grams protein
  • 0.1 gram fat
  • 0.4 gram fiber
  • 18.7 micrograms selenium (27 percent DV)
  • 0.4 milligram riboflavin (21 percent DV)
  • 0.4 milligram copper (18 percent DV)
  • 2.7 milligrams niacin (14 percent DV)
  • 1.1 milligram pantothenic acid (11 percent DV)
  • 86.4 milligrams phosphorus (9 percent DV)
  • 323 milligrams potassium (9 percent DV)
  • 0.1 milligram thiamine (5 percent DV)
  • 0.8 milligram zinc (5 percent DV)
  • 0.1 milligram manganese (5 percent DV)
  • 0.1 milligram vitamin B6 (4 percent DV)
  • 10.1 micrograms folate (3 percent DV)

Mushrooms are unique for a “vegetable” (they are actually a fungus) in terms of their high concentration of B vitamins. B vitamins found in cremini mushrooms include niacin (vitamin B3), pantothenic acid (vitamin B5)and riboflavin (vitamin B2)Pantothenic acid plays a role in many metabolic processes, including turning fats and carbohydrates that we obtain from the foods we eat into energy, and with other B vitamins and nutrient. B5 is needed to fuel the brain, contributing to cognitive health and preventing fatigue.

Higher consumption of B vitamins has been linked to reductions in age-related memory loss, migraine headaches, chronic brain syndrome, depression, motion sickness and insomnia. Other benefits of niacin include balancing cholesterol and blood pressure levels, while riboflavin helps prevent anemia, treat headaches or migraines, lower PMS symptoms, and prevent diseases of the the eyes, including glaucoma.

Perhaps the most convincing reason to eat more mushrooms is due to their anticancer potential. Mushrooms are a cost-effective, safe way to help lower your cancer risk, as they’ve been found to promote decreased tumor cell proliferation and decreased tumor weight, while causing no side effects.

One of the major active components in cremini mushrooms is conjugated linoleic acid (CLA), which has been shown to have protective effects against growth of cancerous cells.

A 2001 study published in the Journal of Nutrition that was conducted on mice found that when the mice consumed mushrooms extract, they experienced a significant reduction in growth of breast cancer cells. The study found evidence that Agaricus bisporus extract suppresses the activity of aromatase (enzyme that breaks down estrogen), resulting in a reduction of estrogen production. Estrogen dominance has been identified as one major contributor to postmenopausal breast cancer in women.  Flavones and isoflavones, found in cremini mushrooms have been shown to help inhibit some of estrogen’s negative effects.

Other studies have found similar positive effects of mushrooms in regard to treating prostate cancer and leukemic monocyte lymphoma.

According to studies, the anticancer compounds found in various species of mushrooms, including cremini play a crucial role in reducing cancer risk by decreasing reactive oxygen species, regulating cell division, regulating angiogenesis (development of blood vessels) and leading to apoptosis (destruction/death of harmful cells).

This is evidence that consuming mushrooms can complement cancer treatments, including chemotherapy and radiation therapy, in addition to reducing common side effects of these treatments, such as nausea, bone marrow suppression, anemia and suppressed immune function.

Ergothioneine (EGT) is a beneficial amino acid that’s found mainly in mushrooms, making them one of the only foods sources available to us. A 2012 study in published Molecular Basis of Disease states, “Studies have demonstrated antioxidant and cytoprotective capabilities of EGT against a wide range of cellular stressors.”

Ergothioneine has been linked to cardiovascular benefits, including reduced inflammation, protection against damaged blood vessels and healthier cholesterol levels, in addition to protection against red blood cell disorders, diabetes or liver damage. It may also help reduce inflammation in the lungs and damage to the kidneys and brain.

Throughout history, a variety of mushrooms have been used as tonics and herbal remedies for treating fatigue, low immune function and weakness, including shiitakes, cordyceps, reishi mushrooms and creminis. Due to their ani-inflammatory and antioxidant properties, they are helpful for increasing immunity against common illnesses like the cold or flu, in addition to infections.

How to Buy

Depending on how the produce department at your supermarket is set up, loose cremini mushrooms might be sold in a bin right beside the regular white mushrooms, or they might be packaged in containers wrapped with plastic. (Avoid the plastic if possible!)

Look for cremini mushrooms that appear to be firm, solid, free from tears, and not shriveled or slippery looking. To clean mushrooms, it’s best not to soak them due to how they absorb a high amount of liquid and can become slippery. Instead remove any residue from the surface of mushrooms using a damp cloth, rag or paper towel. 

How to Store

Because mushrooms contain so much water, they are prone to turning moldy or slimy. The best way to avoid this is to use them as soon as possible. But storing them in the fridge for 2 to 3 days should be fine provided they aren’t encased in plastic, which traps in moisture, leading to the slime.

I like Ambrosia Bags. Ambrosia bag is air permeable and thermo-regulating and help keep mushrooms cool and dry.

How to Cook

The flavor of mushrooms is correlated with their age, both of which are negatively correlated with their moisture content. In short, as the mushrooms age, they get drier and more flavorful. And browner.

Cremini mushrooms are wonderful to use in pastas, soups, casseroles, risottos, quesadillas, tacos, tarts, bruschetta and salads, as well as for making sauces and gravies.

In terms of cooking methods, you can prepare them by sautéing, or roasting, baking, simmering, and you can serve them raw as well. Because cremini mushrooms have less water, it takes them less time to cook.  This makes cremini mushrooms a better choice for dishes where the mushrooms need to be caramelized.



Gluten Free Vegan Mushroom Stroganoff

Bob's Red Mill

6 Servings


  • 1 medium Onion, sliced
  • 1 lb Cremini Mushrooms, diced large
  • 4 large Portobello Mushrooms, sliced
  • 4 Garlic Cloves, minced
  • 1 Tbsp Dairy-Free Butter
  • 1 tsp Paprika
  • ½ tsp dried Thyme
  • Salt and Pepper to taste
  • 1 cup Vegetable Broth
  • ½ cup Red Wine
  • ½ cup unsweetened Dairy Free Milk
  • 6 Tbsp Chickpea Flour
  • ⅓ cup Hummus
  • Gluten Free Pasta, cooked


  1. In a large stock pot, add onion and mushrooms. Add a splash of water as needed, but keep in mind the mushrooms will exude liquid to aid in the cooking process. Cook until onion and mushrooms have softened.
  2. Next add minced garlic, butter, paprika, thyme, salt and pepper. Cook for 1 minute, or until the spices and herbs become fragrant.
  3. Add broth and wine to the onion mixture and cook until the mushrooms are cooked through.
  4. In a small bowl, mix milk and chickpea flour until there are no lumps. Once mushrooms are cooked through, add hummus and the flour mixture, and stir well until the mixture has thickened and there are no lumps.
  5. Serve over your favorite grain or gluten free pasta.



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