I often see discussion of the ethical side of a vegan/vegetarian diet, but I rarely see the serious health concerns properly addressed. People that don’t take a slow, calculated approach to dietary change (of any sort) often end up either reverting back to their old diet, or developing mild to serious health complications. I certainly do urge people to consider the ethical arguments in terms of reducing suffering and increasing sustainability, and to subsequently phase meat out of their diet, BUT I can’t emphasize enough how important it is to consider what’s involved. Not only could the replacements you choose lead to poor health, they could in fact cause more damage to the environment (factors like shipping) or have other unintended side-effects.
Some of the possible health risks I’ve heard of are iron deficiency, vitamin B12 deficiency, blood lipid imbalances (though this study indicates possible benefits, at least as far as hyperlipidemia goes), and as the study just listed states, vegetarian diets are generally lower in sodium, zinc, vitamin A, and “especially omega‐3 polyunsaturated fatty acids”. Vegan diets that entirely avoid animal products magnify some of these risks and introduce new ones like a lack in vitamin K2. Here’s a much more comprehensive look at vegan nutrition. The lack of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) proteins stemming from low omega-3 can be combated in various ways. Chris Kresser makes a number of suggestions including supplementing with microalgae. Another option is oysters.
Oysters don’t have a central nervous system. We have about as much tangible evidence that oysters have the capacity to feel pain as we do for plants. Bivalves having “nerve ganglia” is not a sufficient argument. Here is a post that goes into further detail on the subject. Fleischman states that oysters are sessile, not motile, meaning they can’t even react to pain; therefore there’s no “adaptive reason for them to feel pain”. She also argues that they’re not equipped with opiate receptors or endogenous opiates to inhibit pain. Not only do we have no evidence that oysters feel pain, we have evidence that they have restorative environmental impacts. They can assist with “water quality maintenance, shoreline protection and sediment stabilization, nutrient cycling and sequestration”. There’s also possible applicability in denitrification.
Here is the nutrition label for the oysters I usually get. It’s obvious from the label that they’re high in iron and protein. This article does a great job breaking down some of the other nutritional benefits. Oysters are also high in vitamin B12, omega-3 fatty acids, zinc, selenium, manganese and numerous other vitamins and minerals.
Of course, this topic is pretty broad, and I’ve attempted to summarize a large quantity of information here. I’m sure I’ll have to come back to nutrition in the future. My point is essentially just that oysters are a great way to supplement a vegetarian/vegan diet as they hit some of the key areas where deficiencies seem to develop. While I’m sure arguments of sentience can be made about bivalves, I wouldn’t consider it the most salient of concerns. I encourage everyone to consider including oysters in their diet, even if they’re kind of gross.
Here’s my previous post in this general subject area for anyone interested.