Food Additives Can Enhance Flu Vaccine Efficacy

   

    The inactivated influenza vaccine is the most widely used annual vaccine throughout the world; however, the efficacy of inactivated influenza vaccines is modest in adults and worse in the elderly. An adjuvant is added to or given in conjunction with, a vaccine antigen to enhance the specific immune response. Vaccine efficacy can be improved by the addition of adjuvants, but few adjuvants have been approved for human use (1).

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    To explore novel and effective adjuvants for influenza vaccines, a group of scientists screened 145 compounds from food additives approved in Japan. Of these 145 candidates, they identified 41 compounds that enhanced the efficacy of the split influenza hemagglutinin (HA) vaccine against lethal virus challenge in a mouse model. These 41 compounds included 18 novel adjuvant candidates and 15 compounds with previously reported adjuvant effects for other antigens but not for the influenza vaccine (1). Some of these 41 effective food additives can be obtained from dietary sources. A few of these food additives and their natural food sources (2) are listed below:

 

    Crocin: Crocin is a carotenoid chemical compound that is found in the flowers crocus and gardenia. Crocin is the component primarily responsible for the color of saffron.

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    Methyl anthranilate: Methyl anthranilate naturally occurs in the Concord grapes and other Vitis labrusca grapes and hybrids thereof, and in bergamot, black locust, champak, gardenia, jasmine, lemon, mandarin orange, neroli, oranges, rue oil, strawberry, tuberose, wisteria, galangal, and ylang ylang.

 

    Norbixin: Annatto is an orange-red condiment and food coloring derived from the seeds of the achiote tree native to tropical regions from Mexico to Brazil. The color of annatto comes from various carotenoid pigments, mainly bixin and norbixin, found in the reddish waxy coating of the seeds.

 

    Riboflavin: Riboflavin, also known as vitamin B2, is a vitamin found in food and used as a dietary supplement. Food sources include eggs, green vegetables, milk, and other dairy product, meat, mushrooms, and almonds.

 

   Saponin: Saponins have historically been understood to be plant-derived, but they have also been isolated from marine organisms such as sea cucumber. It is found heavily in Gynostemma pentaphyllum (Gynostemma, Cucurbitaceae) in a form called gypenosides, and ginseng or red ginseng (Panax, Araliaceae) in a form called ginsenosides.

 

    Theobromine: Theobromine is the primary alkaloid found in cocoa and chocolate. Theobromine can also be found in trace amounts in the kola nut, the guarana berry, yerba mate (Ilex paraguariensis), Ilex vomitoria, Ilex guayusa, and the tea plant.

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    It is reasonable to speculate that the foods containing these compounds may help with our immune protection as these components were shown with significantly prevented deaths of the mice from a lethal dose of flu vaccine (1). These foods, such as Concord grape, ginseng, saffron, cocoa, and tea, have been well-known for many health benefits. They are good food choices to be included in the diets. Please feel free to contact us if you may have any questions on this topic or if you would like to learn more details about the many health benefits of these food components.

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References:

1. Feng H, Yamashita M, Wu L, Jose da Silva Lopes T, Watanabe T, Kawaoka Y. Food Additives as Novel Influenza Vaccine Adjuvants. Vaccines (Basel). 2019. 7(4). pii: E127.

2. Food sources from Wikipedia