Natural Killer Cells are high and low in a variety of conditions. They can contribute to and prevent disease. Do YOU have low or high Natural Killer Cells?

Intro to Natural Killer (NK) Cells

Natural Killer (NK) cells are a type of toxic lymphocytes that are critical to the immune system.

NK cells are produced in the bone marrow, lymph nodes, spleen, tonsils, and thymus, where they then enter into the circulation.

They control several types of tumors and microbial infections by limiting their spread and future tissue damage that can occur.

The cells become active around 3 days after infection and respond to tumor formation in the body.

NK cells monitor tumors that may grow by directly triggering the death of tumor cells.

They have the ability to recognize stressed cells without having to have previous exposure to the pathogens, allowing for a fast immune reaction.

NK cells can develop long-lived and highly specific memories to a variety of targets [1].

Extreme genetic diversity is present in both mice and humans coding for NK cells [2].

What Function Does Natural Killer Cells Have?

Individuals lacking NK cells have regular viral infections and die prematurely [3].

Individuals deficient in NK cells are prone to early phases of herpesvirus infection [4] and NK cells help fight HIV.

Mice with less NK cell function are more prone to cancers [2].

Activation of NK Cells

Circulating NK cells remain in their resting phase. NK cells activated by cytokines lead to the invasion of these cells into tissues with pathogen-infected cells [5].

When activated, they secrete cytokines such as interferons [5] and TNF-a [6].

NK cells release a membrane-disrupting protein, perforin, which causes cell death of the target cell [5].

So perforin perforates the “skin” of the pathogen [7].

Conditions With Elevated Natural Killer Cells

Obesity promotes the expression of inflammatory genes in the abdominal fat.

It elevates the number and activity of NK cells in only the stomach fat.

When NK cells are removed, inflammation in abdominal fat is suppressed and insulin resistance is improved.

NK cells control insulin resistance by transmitting proteins that affect macrophages [8].

In Asthma, NK cells contribute to IgE mediated immune-responses and may exacerbate the condition [5].

In Type 1 diabetes, NK cells increase the destruction of the pancreas [5].

Higher NK cells form in women who have reoccurring miscarriages [9].

Th1 Dominance and NK Cells

Th1 dominance (IL-12, IL-2) increases NK Cell activity [10].

On the other hand, NK cells may, in turn, destroy and suppress Th1 cells [11].

I actually don’t do very well with the more potent stimulators of NK Cells. This could either be because I don’t do well with NK cell stimulants, or because NK Cell stimulators have other immune boosting properties – or both.

Conditions That Have Low Natural Killer Cells

Impairment of Natural Killer cells is also associated with advanced aging [12].

Natural Ways to Increase Natural Killer Cells

These strategies lead to increased natural killer cells.




Natural Ways to Enhance Natural Killer Cell Function

These strategies lead to increased function or cytotoxicity of Natural Killer Cells.


  • Exercise [13]
  • Strength training [33]
  • Antioxidants [34]
  • Massage therapy [14]
  • White button mushrooms [35]

Supplements (if overactive immune system)

These supplements are safe if you are Th1 dominant and have an overactive immune system, but you’d still like to stimulate NK Cells.

Supplements (if underactive immune system)

Other: LSD [62]


NK Cell Inhibitors

NK Cell Cytotoxicity Inhibitors

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