Plants are good for you, so why do wellness influencers call them toxic?

Beyond evaluating the claim itself, this fact-check will consider how the argument that “most plants are not good for you” is presented. Misinformation often extends beyond isolated factual inaccuracies; it is shaped by the broader narratives that tie those claims together.

In this case, Dave Asprey does not cite any scientific studies to support his argument that oxalates make most plants unhealthy. Instead, he presents the idea through storytelling, a method that can be compelling but should always be weighed against scientific evidence. 

What are oxalates, and where does the claim that oxalate-containing foods should be avoided come from?

The idea that oxalate-rich foods should be avoided was popularised by Sally K. Norton in her book Toxic Superfoods, where she argues that oxalates contribute to a range of health problems. The most commonly shared concern is the risk of developing kidney stones, which Dave Asprey also mentions in this post.

Oxalates are naturally occurring compounds found in many plant foods, including leafy greens, beans, and nuts. They can bind to calcium in the digestive tract, forming calcium oxalate, a major component of kidney stones. Contrary to Dave Asprey’s claim that many plant foods contain oxalates “far in excess of what your body can handle,” in most people, oxalates are safely excreted through urine and stool without causing issues.

Since kidney stones often contain calcium oxalate, it might seem intuitive that avoiding oxalate-rich foods could prevent stone formation. However, research suggests that dietary oxalate is one factor in stone development, and context matters when assessing risk.

For example:

• Calcium intake is important: When consumed together, dietary calcium binds to oxalates in the gut, preventing absorption into the bloodstream. Dr. David Goldfarb recommends consuming dairy or other calcium sources alongside oxalate-containing foods rather than eliminating them.
• Hydration plays a key role: Drinking enough fluids helps dilute oxalates in the urine, reducing the likelihood of kidney stone formation.
• Overall diet matters more than individual compounds: This meta-analysis shows that overall vegetable intake and total fibre intake were consistently linked to a reduced risk of kidney stones. Beyond concerns related to kidney stones, numerous studies indicate that plant-based diets are associated with a lower risk of chronic disease, contradicting the idea that oxalates should be avoided entirely due to inherent harm.

Dave Asprey’s statements don't take into account the fact that plant-based diets can be recommended to reduce the risk of kidney stones. For example, in this review of the available evidence on the role of diet in kidney stone prevention, researchers concluded that “a balanced vegetarian diet with dairy products seems to be the most protective diet for kidney stone patients.” 

The argument that oxalate-rich foods should be avoided because of kidney stones is reductive in the sense that it appeals to the cherry-picking fallacy, where only the information which supports the author’s narrative or diet is selected, while contradictory evidence is left out.

For a deeper exploration of the claim that oxalate-containing foods should be avoided because of their association with kidney stones, you can read our full fact-check here.

Oxalates and Brain Health

Dave Asprey also says that oxalates are a common cause of many other health issues, including IBD, PCOS, brain fog, and even brain lesions. “This is oxalate forming through the body, it calcifies you, makes you old, causes brain lesions.”

We have reached out to experts in brain health to discuss this alleged association between oxalates and accelerated ageing: