Over the next few articles, we explain how your immune system helps fight viral infections and how AHCC® may help: 

• Article 1: how AHCC® supports the immune system
• Article 2: how ageing and poor health affect immunity, and how AHCC® may help
• Article 3: how viruses evade the immune system and how AHCC® may help.

Let’s start by looking at how AHCC® supports the body’s natural defences.

What is AHCC®?

Active Hexose Correlated Compound (AHCC®) is a natural supplement made from the root-like part of the shiitake mushroom, called mycelia. 

Unlike many mushroom supplements, AHCC® contains high levels of alpha-glucans, naturally-occurring carbohydrates thought to play a role in supporting the immune system. It also contains amino acids (the building blocks of protein), minerals, and other naturally occurring compounds (Matsui et al., 2002).

How AHCC® supports immune cells directly

For more than 20 years, scientists have studied AHCC® to understand how it supports the immune system. Research suggests it may help the body fight infections, strengthen immune function and support the body’s natural defences against viruses. 

Although scientists are still learning exactly how AHCC® works, current evidence suggests it supports immunity in two main ways:

• It directly activates and regulates immune cells.
• It may improve gut health, which also plays an important role in immunity. 

Of these two, the direct effects on immune cells has the strongest scientific evidence (Roman et al., 2021; Yin et al., 2010).

After you take AHCC®, it reaches your digestive system, where it comes into contact with immune cells in the gut. In fact, much of your immune system is located here, in an area called the gut-associated lymphoid tissue (GALT). This is a collection of immune cells that help protect the body from harmful germs entering through the digestive tract.

Research suggests that AHCC® activates receptors (specialised proteins that detect potential threats) on these immune cells, helping them to recognise and  respond more effectively to viruses and other harmful microbes (Yin et al., 2010).

AHCC® and Natural Killer (NK) cell activity 

One of AHCC®'s most-studied effects is its ability to increase the activity of natural killer (NK) cells. 

NK cells are one of your body's first line of defence against infection. They patrol the body looking for virus-infected or abnormal cells and can destroy them quickly without needing to recognise a specific virus.

 Studies in both people and animals have shown that AHCC® can increase both the number of NK cells and how effectively they work, helping strengthen the body's natural defences against infections and disease (Ritz et al., 2006; Terakawa et al., 2008).

AHCC®, macrophages and dendritic cells

AHCC® also appears to support two other important types of immune cells:

• Macrophages act as the body's clean up team. They engulf and remove bacteria, viruses and damaged cells. They also release chemical signals that call other immune cells into action. 
• Dendritic cells act like scouts. They identify invading germs and alert the rest of the immune system, helping it launch a faster and more targeted response. 

Research suggests that AHCC® helps these cells mature and work more effectively (Yin et al., 2010).

AHCC® and T cells (adaptive immunity)

AHCC® may also support the adaptive immune system, the part of the immune system that learns to recognise specific infections and provides longer-lasting protection. 

Studies suggest AHCC® may increase the activity of:

• Helper T cells (CD4 cells) which coordinate the immune response by directing other immune cells.
• Cytotoxic T cells (CD8 cells), which destroy infected and abnormal cells. 

Together, these effects may improve the body's ability to control long-term viral infections and maintain healthy immune defences (Roman et al., 2021).

AHCC® and cytokine signalling

Immune cells constantly communicate with one another using tiny chemical messengers called cytokines.

Research suggests AHCC® increases the production of several cytokines involved in fighting viral infections.

Rather than simply making the immune system work harder, AHCC® appears to help immune cells communicate more effectively while maintaining a healthy balance (Yin et al., 2010; Roman et al., 2021).

The gut-immune connection: How AHCC® supports gut health

AHCC® may also support immunity by promoting a healthier digestive system. 

Scientists estimate that around 70-80% of the body's immune cells are found in or around the gut, making digestive health an important part of  overall immune function (Belkaid & Hand, 2014).

The lining of the intestine acts as both a physical and immune barrier. It allows nutrients into body while helping prevent harmful bacteria, viruses, and toxins entering the bloodstream. 

Some animal studies suggest that AHCC® encourages the growth of beneficial gut bacteria such as Lactobacillus and Bifidobacterium. 

These ‘friendly’ bacteria help keep the gut microbiome (the community of microbes living in your digestive system) healthy. They also produce short-chain fatty acids, including butyrate, acetate, and propionate. These nourish the cells lining the intestine, strengthen the gut barrier, and help regulate the immune system (Makki et al., 2018).

One of these fatty acids, butyrate, is especially important because it helps keep the intestinal lining healthy and supports regulatory T cells – immune cells that prevent excessive inflammation and stop the immune system from overreacting (Koh et al., 2016; Makki et al., 2018).

AHCC® has also shown antioxidant and anti-inflammatory effects in laboratory and animal studies. This may help protect the gut lining from damage and make it less likely that harmful bacterial toxins leak into the bloodstream, where they could contribute to long-term inflammation.

Although these findings are promising, the evidence for AHCC®'s effects on gut health is still developing. Most studies have been carried out in animals or in the laboratory, and more high-quality human studies are needed. 

For this reason, researchers generally consider improvements in gut health to be a possible secondary benefit of AHCC®, while its direct effects on immune cells remain the main mechanism supported by research (Roman et al., 2021).

The bottom line: Is AHCC® an immune-modulating supplement?

Current research suggests that AHCC® supports the immune system primarily by helping immune cells work more effectively. 

Studies shows it may enhance the function of natural killer cells, macrophages, dendritic cells, and T cells while also improving communication between these cells through cytokines. These direct effects have been demonstrated in both laboratory research and human clinical studies (Ritz et al., 2006; Terakawa et al., 2008; Roman et al., 2021).

AHCC® may also provide additional immune support by promoting a healthier gut microbiome, strengthening the intestinal barrier, and helping to reduce inflammation. However, more human research is needed to fully understand these benefits.

Overall, the evidence indicates that AHCC® is best described as an immune-modulating supplement. In other words, rather than simply boosting the immune system, it helps it respond appropriately and maintain a healthy balance. 

This balanced immune response may help support your body's natural defences and contribute to better long-term health.

References

Belkaid, Y., & Hand, T. W. (2014). Role of the microbiota in immunity and inflammation. Cell, 157(1), 121–141.

Koh, A., De Vadder, F., Kovatcheva-Datchary, P., & Bäckhed, F. (2016). From dietary fiber to host physiology: Short-chain fatty acids as key bacterial metabolites. Cell, 165(6), 1332–1345.

Makki, K., Deehan, E. C., Walter, J., & Bäckhed, F. (2018). The impact of dietary fiber on gut microbiota in host health and disease. Cell Host & Microbe, 23(6), 705–715.

Matsui, Y., Uhara, J., Satoi, S., et al. (2002). Improved prognosis of postoperative hepatocellular carcinoma patients when treated with functional food: A prospective cohort study of AHCC®. Journal of Hepato-Gastroenterology, 49, 418–422.

Ritz, B. W., Nogusa, S., Ackerman, E. A., & Gardner, E. M. (2006). Supplementation with Active Hexose Correlated Compound increases the innate immune response of young and aged mice. Journal of Nutrition, 136(11), 2868–2873.

Roman, B. E., Beli, E., Duriancik, D. M., et al. (2021). Active Hexose Correlated Compound (AHCC®): A systematic review of its immunological effects and clinical applications. Nutrition and Cancer, 73(10), 1733–1749.

Terakawa, N., Matsui, Y., Satoi, S., et al. (2008). Immunological effect of Active Hexose Correlated Compound (AHCC®) in healthy volunteers: A pilot study. Nutrition and Cancer, 60(5), 643–651.

Yin, Z., Fujii, H., & Walshe, A. (2010). Effects of Active Hexose Correlated Compound (AHCC®) on immune function: A review. Journal of Nutrition, 140(9), 1681S–1686S.