It’s one of the top 10 killers in the US, causing an average estimate of over 30,000 people to die each year.1,2 It’s not heart disease or cancer or diabetes… it’s the flu.
Most people associate the flu with muscle pain, coughing, sore throat, fatigue, and other symptoms, but the flu can turn into a deadly infection.2,3
Scientists have found two ingredients that prime the immune system to defend against the onslaught of influenza and other seasonal pathogens that can result in serious illness and even death.2,4,5
The Deadly Complications of Influenza
If you think of the flu as merely a seasonal risk or inconvenience, think again. Although known for uncomfortable symptoms such as sore throat, nasal discharge, chills, fever, muscle pain, headaches, coughing, nausea, and fatigue3,6—the harsh reality is that tens of thousands of Americans die from influenza infection in an average year.
Potentially lethal results of the flu can include either direct viral pneumonia or secondary bacterial pneumonia,7,8 and complications of chronic conditions such as congestive heart failure and chronic obstructive pulmonary disease (COPD).9
Almost 90% of all American deaths caused by influenza are among those over 65 years old.10 One reason is the immune senescence suffered by virtually all aging individuals. Vaccines function by eliciting an antibody response against specific viruses . The ability to generate an antibody response to influenza vaccines is severely compromised in the elderly.11
But the elderly are not the only ones at risk of flu-related death. High-risk groups also include pregnant women, the immunocompromised, children under age two, and people who have chronic illnesses such as asthma, diabetes, heart disease.12
The Best Defense Against the Flu
Receiving an annual flu shot is an effort many individuals, particularly those over age 65, make in an attempt to prevent both influenza infection and its deadly outcomes.13 The reason is that it mobilizes what is known as adaptive or acquired immunity.14 After the body has been “primed” with specific, non-infective viruses in the form of a vaccine, the immune system can then make antibodies to protect against future infection with these viruses.14
However, for a flu vaccine to even begin to protect against the influenza virus contained within it, the vaccinated individual must first have sound immune function—so that the immune system can properly respond to stimulation by the vaccine’s antigen.15
The trouble is that, in those with weakened immunity—such as the elderly population—vaccine stimulation triggers only a limited antibody response, thus limiting the effectiveness of the vaccine.16,17
That means, despite being vaccinated, aging individuals remain highly susceptible to infection. This can be one reason why up to 91% of those 65 and over who get a flu shot may still be susceptible to getting the flu!18
But there’s good news. Scientists have recently found a way to boost the effectiveness of the flu vaccine. Exciting new evidence shows that, taken together for two weeks prior to vaccination, the amino acids L-theanine and L-cystine enhance the efficacy of the flu vaccine in certain subsets of elderly subjects.19 This delivers strong protection against the flu virus—and its deadly complications.
These two compounds do not enhance the vaccine itself; instead, they help boost the immune system’s acquired immune response, giving your body the tools it needs to effectively utilize the vaccine.19
When these complementary amino acids were used together in animal studies, they increased immune response.4,20
In one study, researchers gave both L-theanine and L-cystine orally to mice for 10 days. Six days after infection with influenza, the treated mice had lower lung concentrations of the virus. Ten days after infection, there was a significant enhancement of key anti-influenza-virus antibodies (called immunoglobulin G or IgG).4
Scientists realized that the co-administration of L-cystine and L-theanine could restore age-related impairment of immune competence, helping to prevent influenza and other viral infections—and in turn, preventing deadly complications.4
Based on this knowledge, scientists set out to determine if these two substances could boost vaccine effectiveness by targeting (and enhancing) the immune system itself.