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Research Critique

Dietary Wolfberry Supplementation Enhances the Protective Effect of Flu Vaccine against
Influenza Challenge in Aged Mice

Lorraine Bonkowski
NFS 4250: Advanced Human Nutrition
February 3, 2015

Every year about 36,000 deaths occur from influenza infections. The majority of these
deaths are of people aged 65 years and up, mostly because of their decreased immune function.
Although vaccines are usually effective in preventing influenza, there is an impaired response in
the elderly. Because of this, researchers have been looking for ways to improve the effectiveness
of vaccines for the elderly in order to decrease the amount of deaths caused by influenza
infection. Wolfberry, also known as goji berry, has recently been found to have antioxidant, anti
tumor, neuroprotective, and immunoenhancing health benefits. It has already been shown in the
elderly that a milk-based preparation of wolfberry helps elevate the antibody titers after an
influenza vaccination has been given1.
The main focus of the study was to see if wolfberry increases the power of a vaccines
effectiveness to protect a host after being infected by influenza. A hypothesis for this study could
be that the addition of wolfberry in a diet will have no effect on the influenza vaccines ability to
protect a host after being infected with influenza.
In the study, aged mice ranging from 20 to 22 months of age were used to see the effect
of wolfberry on the vaccines efficacy. The aged mice were randomly divided into 4 groups and
each group had 13 mice. Two of the groups were given a standard diet supplemented with a 5%
milk-based preparation of wolfberry to serve as the experimental groups. The two other groups
were given a standard diet supplemented with 5% corn starch to serve as the control. The mice
consumed their assigned diet for the entire experiment. Next, only one group of mice from the
wolfberry diet and one group from the control diet were immunized with the influenza vaccine
on day 31 of the experiment and then injected again on day 52 with a booster. On these days, the
remaining groups were injected with saline to serve as the controls. On day 66, the blood work of

all the mice was collected to view their antibody titers and then on day 73, all the mice were
infected with influenza1. After this, daily weight loss and death of the mice were recorded.
The results of the experiment showed that the diet supplemented with wolfberry may
enhance the hosts overall protective effect of the influenza vaccine. They determined this by
looking at the increase in antibody response and decrease in weight loss. Two weeks after the
booster vaccine was given and before the virus was introduced, blood was collected from the
mice. The blood results showed that the experimental mice consuming the wolfberry diet had
significantly higher hemagglutination inhibition titers and immunoglobulin titers (P < 0.05),
which are both indicators of an increased antibody response, than the mice eating the control
diet. When it came to measuring weight loss of the vaccinated mice, after the virus infection,
there was a significant effect from diet (P < 0.001). The researchers previously determined that
weight loss is a good indicator for measuring how severe the influenza illness impacts the host.
The experimental mice that had the wolfberry diet only lost 5% of their original body weight
while the mice with the control diet lost more than 10%1. The control mice that received only the
saline injection, regardless of their diet, lost 20% of their original body weight.
I believe that the results of the experiment were valid in showing that wolfberry may
increase the protective effects of the influenza vaccine. The researchers had appropriate P values
to show significance in their findings. The results for increased antibody response had a P value
of less than 0.05 so the researchers only had a 5 percent chance of being incorrect. The results
that showed the weight loss in mice had a P value of less than 0.001 so the researchers only had a
0.1 percent chance of being incorrect. I also did not see any evidence that the research could
have been biased. I think that there were several well controlled variables of the experiment. The

mice were contained in a controlled environment with constant temperature and humidity. They
were all exposed to the same light cycle of 12 hours of light and then 12 hours of darkness. Each
mouse was randomly selected and housed individually1. There were also a few variables I
thought to be not well controlled. All the mice were provided water and food without limit.
Maybe the mice that consumed more food and water would have been stronger to fight the
influenza infection than the ones that didnt. Also, the study stated that the mice were randomly
placed into their groups however it did not mention anything that the mice were randomly
selected for the overall experiment. When it comes to relating this experiment in humans, there
are many different strains of influenza and this experiment only tested one kind. Perhaps the
wolfberry would be effective in increasing the vaccines efficacy against only that strain of
influenza and not as effective with another strain. However, I think that this experiment overall
shows impressive results about how diet can really make an impact on our health. Hopefully
these findings will lead to more experiments to help researchers prevent more deaths from
influenza in the elderly and the overall population.

1. Du X, Wang J, Niu X, Smith D, Wu D, Meydani SN. Dietary wolfberry supplementation
enhances the protective effect of flu vaccine against influenza challenge in aged mice. J.
Nutr. 2014; 144: 224-229.