How to boost natural killer cell activity and avoid health problems
(NaturalHealth365) What exactly are these natural killer cells (NK cells)? The name of these immune cells sounds as if it’s straight out of a Hollywood movie.
And, the truth behind NK cells is just as dramatic as their title indicates. Research has revealed natural killer cells as an elite force of biological commandos, laser-focused on destroying cancerous or infected cells and slowing the growth of tumors.
Now, a scientific review published in the prestigious Journal of Immunology Research supports the ability of natural nutrients and supplements to boost the disease-fighting powers of NK cells even further. Let’s take a look at some of the mechanisms NK cells use to protect us from illness – and explore nutrients and herbs that can provide them with “tactical support.”
Discover how natural killer cells effectively destroy diseased and infected cells
NK cells are lymphocytes – specialized white blood cells that are present in every tissue in the body. Also found in the placenta, NK cells may play a key role in pregnancy.
Basically, natural killer cells destroy their prey in two different ways. In addition to releasing cell-killing (cytotoxic) granules such as perforin – which creates lesions in cellular membranes – NK cells can induce apoptosis, or programmed cell suicide.
While other cells must be “primed” or activated by other parts of the immune system to attack and kill diseased cells, natural killer cells are more than ready to act completely on their own. In addition to killing infected and cancerous cells, NK cells secrete cytokines which help to enhance the immune response.
Obviously, natural killer cells are tremendously important allies against potentially life-threatening infections and cancer. But, they are not indestructible. NK cells can be depleted by a variety of factors, including poor nutrition, processed foods, chronic physical and mental stress, exposure to environmental toxins, excessive alcohol use and smoking cigarettes.
This, of course, can increase the risk of both acute and chronic illness. Fortunately, natural techniques exist to support and promote natural killer cell populations.
Help to protect your health with the body’s “master antioxidant”
Glutathione, often referred to as the body’s “master antioxidant,” excels at neutralizing toxins in the body. Another important contribution to health is its ability to optimize and enhance the disease-fighting power of NK cells, keeping them “primed for defense.”
In an influential double-blind, placebo-controlled study published in 2015 in European Journal of Nutrition, 54 adults were given 250 mg of glutathione, 1,000 mg of glutathione or a placebo daily. After three months, the high-dose glutathione group experienced an impressive doubling in the cytotoxic (cell-killing ability) of their natural killer cells, when compared to those who had taken a placebo. The group also experienced substantial reductions in oxidative stress.
You can increase your glutathione levels by consuming foods rich in cysteine, one of glutathione’s “building blocks.” Cruciferous vegetables, such as Brussels sprouts and broccoli, are particularly good sources, along with garlic and onion.
You can also ramp up glutathione levels with vitamin C, vitamin E, alpha lipoic acid and N-acetyl cysteine (NAC). Natural health experts typically recommend glutathione dosages between 250 and 500 mg per day. However, check with your integrative doctor before supplementing.
Send in the reinforcements: Consuming garlic and curcumin can help take natural killer cells to the next level
In a review published in Journal of Immunology Research, the authors credited aged garlic extract with increasing the number and activity of NK cells in patients with liver, pancreatic or colon cancer. And, daily injections of a fresh garlic extract caused an increase in NK cell activity in mice with tumors – and significantly decreased tumor growth.
There was more exciting news involving curcumin, the active ingredient in from turmeric. With strong antioxidant and anti-inflammatory effects, curcumin is being investigated worldwide for its anticancer properties.
The authors noted that curcumin caused elevated production of nitric oxide by NK cells, “thereby causing apoptosis in target cancer cells.” In another study, megadoses of curcumin administered in conjunction with omega-3 fatty acids increased NK cell-induced apoptosis of pancreatic cancer cells.
While more research is needed, the ability of these natural compounds to stimulate NK cell activity is certainly promising! Other herbal substances that can support NK cell function include ashwagandha (Withania somnifera) cat’s claw (Uncaria tomentosa), echinacea and medicinal mushrooms such as cordyceps and reishi.
Vitamins that support NK cell activity
In a 2015 cell study published in Cytology, 1,000 mg a day of ascorbic acid (vitamin C) was shown to boost NK cell populations. The scientists noted that the addition of ascorbic acid caused NK cells to proliferate and to mature more quickly, without influencing their functionality.
In other research, pairing vitamin C with red ginseng promoted NK cell activity even more strongly.
Vitamin D can be helpful as well. In one study, supplementation with vitamin D caused a rise in the expression of NK-activating receptors, while downregulating a receptor that inhibits NK function.
Vitamin D, which is vital for proper immune function, can be obtained through exposure to sunlight. But, depending on where you live, you may need supplementation to reach optimal levels.
And vitamin E shows promise, as well. In studies of aging mice, researchers found that alpha-tocopherol (the natural form of vitamin E) could potentially combat age-related decline in NK cell function, enhancing activity and restoring cytotoxicity.
In one clinical study, dietary intake of higher vitamin E doses improved the activity of NK cells in patients suffering from colorectal cancer. Naturally, you should check with your integrative physician before adding any supplements to your daily routine.
Take a hike: “Forest bathing” yields surprising health benefits
Dr. Bill Rawls, MD, an expert on herbal and alternative medicine, recommends promoting healthy NK cell populations through low-intensity, consistent exercise such as walking.
For maximum benefit, Dr. Rawls advises walking in the pine-scented air of a forest in order to gain exposure to phytoncides – beneficial antimicrobial compounds released by plants. Also known as “forest bathing” and “Shinrin-yoku,” this practice has been shown to raise natural killer cell activity by up to 50 percent.
Keep in mind, when forest walking, take precautions against biting insects, particularly ticks. According to Dr. Rawls, ticks can carry “stealth” microbes, which can manipulate the immune system and suppress NK cells.
Other steps you can take to support natural killer cell activity include eating an organic diet, avoiding cigarettes and alcohol plus managing stress through acupuncture, yoga, guided meditation, biofeedback or Qigong.
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