Are oysters really aphrodisiacs or just a Valentine's Day marketing ploy?

an Ad campaign by Publicis Montreal for the 2014 Voir Restaurant Guide.


an Ad campaign by Publicis Montreal for the 2014 Voir Restaurant Guide.

When February comes around each year, the media capitalizes on Valentine's Day with articles on romantic gift ideas, outings, pink flowers and candy, you name it. And when it comes to food, one common topic of discussion is aphrodisiacs, foods that stimulate sexual desire.

Oysters have long had the reputation of being an aphrodisiac. They say that Casanova, the French adventurer/womanizer, used to eat fifty oysters a day. Perhaps that's what helped him get all the ladies! So does it work? Are oysters really aphrodisiacs? Or is this all a marketing ploy to generate more oyster sales during February?

Let's Investigate the science

Until 2005, no research had really been done on the oyster's stimulating properties. It was generally believed to be a placebo effect. So when a team of American and Italian researchers made their findings public, the news made headlines.

According to the researchers, oysters and other bivalves contain rare amino acids (chemical compounds that form proteins)*, which are not commonly found in nature. These two amino acids -- D-aspartic acid (D-Asp) and N-methyl-D-aspartate (NMDA) -- play a role in hormone synthesis. D-aspartic acid has been found to temporarily increase testosterone levels and improve sperm motility. NMDA is an agonist (a substance that initiates a physiological response) that can increase neural excitability. When the scientists injected rats with these amino acids, they found increased testosterone production in males and increased progesterone production in females, hormones that increase libido.**

Spring, when the molluscs themselves are breeding, is best. There is the highest concentration of these two amino acids then... Oysters have to be eaten raw to be most effective. Cooking them reduces the quantity of D-Asp and NDMA molecules.
— Dr. George H. Fisher, Barry University

The results of this study sounded very promising, but other scientists are skeptical, pointing out that animal studies may not be relevant to humans, and until a study is done using human subjects, it's hard to conclude that oysters have a direct correlation in increasing libido.

So yes, there is some scientific proof that oysters and bivalves promote sexual desire, but libido aside, there are other reasons why you should be consuming shellfish this Valentine's Day:

The Nutritional Benefits

fatty acid composition
  1. Low in saturated fats aka "Bad Fats"
    As you can see from the chart on the right, shellfish tend to have less saturated fats (popularly known as "Bad Fats") than other proteins like beef, pork, and chicken. Instead, they are very high in unsaturated fats ("Good Fats" like omega-3 fatty acids) and when eaten in moderation, can help lower cholesterol and reduce risk of heart disease.
     
  2. High in protein and low in calories
    Did you know that 100 g of mussels has about the same amount of protein as 100 g of steak or chicken? And it also has less calories than both of the other options!
     
  3. Rich in vitamins and minerals especially for iron, zinc, copper, and vitamin B-12
  • Iron promotes healthy hemoglobin, the molecule that transports oxygen in red blood cells. 100 g of shellfish contains about 7 mg of iron while the same amount of beef or lamb contains only 2.6 mg.
     
  • Zinc is essential for the immune system and cellular metabolism. Researchers have also found that zinc promotes sperm production, which can be another sign that bivalves are aphrodisiacs. 100 g of oysters has about 80 mg of zinc compared to 8 mg in beef of the same portion.
     
  • Copper also assists with the production of hemoglobin and collagen, and one 100 g serving of raw oysters (1.58 mg) provides more than the daily recommended value for adults (0.9 mg).
     
  • Vitamin B-12 plays a key role in the normal function of the brain and nervous system, and for the formation of blood. It's found in most meat products, but shellfish is a good source for B-12s especially if you're pescetarian.

Besides the nutritional benefits, shellfish is also a sustainable protein and seafood source. We won't go into all the details because that can be a post all on its own, but know that by choosing shellfish, you're also doing the planet good!

So this Valentine's Day, order a dozen oysters or some steamed mussels. We will thank you, the planet will thank you, and maybe your special someone will thank you too...

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References

*D'Aniello, et al. A specific enzymatic high-performance liquid chromatography method to determine N-methyl-D-aspartic acid in biological tissues. Analytical Biochemistry. 2002 Sep 1; 308 (1): 42-51.

**D'Aniello, et al. Involvement of D-aspartic acid in the synthesis of testosterone in rat testes. Life Sciences. 1996; 59 (2): 97-104.

Topo E, et al. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reproductive Biology Endocrinology. 2009 Oct 27; 7:120.

Dong, F.M. The Nutritional Value of Shellfish. 2009 University of Washington.