Dave Asprey's Case Against Kale
Dave Asprey's position on kale is clear and unwavering: avoid it at all costs. His criticism stems from a deeply held philosophy that many plants contain defense chemicals, or 'antinutrients,' designed to protect them from being eaten. While kale is often celebrated for its vitamins and minerals, Asprey argues that its potential harm, especially when consumed in large quantities, outweighs its benefits. He has frequently used his platforms, including The Human Upgrade Podcast, to detail his concerns, sharing his own personal experience with excessive kale consumption during his raw vegan phase.
The Oxalate Overload
One of Asprey's primary concerns with kale is its oxalate content. Oxalates are naturally occurring compounds that can bind to minerals like calcium in the gut, inhibiting their absorption. When present in high amounts, oxalates can form crystals in the body, which can lead to various health problems. Asprey highlights the risk of kidney stones, which are often composed of calcium oxalate. He cautions that while some people can tolerate small amounts, consuming large quantities through green smoothies or juicing can overwhelm the body's ability to process them. This is a concern he has shared with others, including on an episode of Joe Rogan's podcast.
The Threat of Toxic Metals
Beyond oxalates, Asprey raises alarming concerns about kale's ability to accumulate toxic metals from the soil, such as thallium. He describes kale as a "garbage collector plant" that can absorb and store heavy metals that are more toxic than lead. According to Asprey, this makes it a potentially dangerous food source, especially for those seeking to optimize their health. He also claims that kale can accumulate PFAS, or "forever chemicals," further cementing his view that it should be avoided. These claims, however, are met with skepticism by some and are a point of controversy within the nutrition community.
Comparison: Asprey's View vs. Conventional Wisdom
To understand the full scope of the debate, it's helpful to compare Asprey's perspective on kale with the conventional nutritional viewpoint.
| Aspect | Dave Asprey's View | Conventional Nutritional View |
|---|---|---|
| Oxalate Content | High in oxalates, especially when consumed in large, raw quantities in smoothies. | Kale has relatively low oxalate content compared to spinach or swiss chard. |
| Toxic Metals | A "garbage collector plant" that accumulates thallium, PFAS, and other heavy metals from the soil. | While plants can absorb heavy metals from contaminated soil, this is not a widespread issue for commercial kale. |
| Antinutrients | Plants, including kale, contain defense chemicals like oxalates that are harmful to humans. | Antinutrients exist but typically pose no threat in standard diets. Proper preparation (cooking, steaming) can reduce their levels. |
| Inflammation | Believes oxalates and other plant toxins in kale contribute to chronic inflammation. | Kale is widely considered an anti-inflammatory food, rich in antioxidants and flavonoids. |
| Overall Health | Avoid at all costs for optimal health and longevity due to antinutrients and toxins. | A nutrient-dense vegetable and a valuable part of a balanced diet, offering numerous health benefits. |
The Role of Goitrogens
Another concern, though less emphasized by Asprey, is that cruciferous vegetables like kale contain goitrogens, which can interfere with thyroid function. For most people, this is not an issue, especially when kale is cooked. However, Asprey's followers often take a more cautious approach, viewing goitrogens as another potential "anti-nutrient" to minimize or eliminate. Steaming or cooking kale can significantly reduce its goitrogen content, but Asprey's broader argument is that these compounds, along with oxalates and heavy metals, make kale a suboptimal food choice.
Biohacking Alternatives to Kale
For those who follow Asprey's biohacking principles and wish to avoid kale, there are numerous alternatives for getting micronutrients without the potential downsides he highlights. The emphasis is on choosing greens with lower antinutrient levels or preparing them in ways that minimize them.
- Safe Greens: Asprey often recommends vegetables like celery, cucumber, and leafy lettuce, which are generally lower in oxalates.
- Fermented Vegetables: Fermenting vegetables can break down antinutrients and enhance nutrient bioavailability.
- Cooking and Steaming: Heat can significantly reduce oxalate and goitrogen levels in greens. Steaming kale for a few minutes can make it a safer option.
- Organically Grown: While not a guarantee against all toxins, sourcing from trusted, clean farms can reduce exposure to environmental contaminants.
The Importance of Context
It is crucial to recognize that Asprey's dietary recommendations are part of a larger biohacking protocol aimed at high-performance and longevity. The average person, who consumes a varied diet and does not have specific sensitivities or health issues, is unlikely to experience adverse effects from including moderate amounts of kale. However, his strong stances have successfully raised awareness about plant compounds like oxalates and the importance of preparing certain foods correctly.
Conclusion: A Controversial Take on a Superfood
Dave Asprey's perspective on kale is highly controversial, painting a picture of the leafy green as a health hazard rather than a superfood. His arguments center on the alleged dangers of oxalates, heavy metals, and other plant compounds, which he believes can lead to serious health issues, including kidney stones and inflammation. While conventional nutrition science often contradicts his claims regarding kale's oxalate levels, his message has resonated with the biohacking community. Ultimately, whether to follow Asprey's advice and avoid kale depends on an individual's personal health philosophy, biological sensitivity, and willingness to trade widely accepted nutritional guidance for an alternative approach focused on minimizing plant defense chemicals.
