6 Additives and Toxins that Hide in Healthy Food

By: Dave Asprey

The Bulletproof Diet Roadmap (check it out for free here) provides a simple spectrum: The “Bulletproof foods” in green are most likely to help you thrive, the “Kryptonite foods” in red are have more toxins than nutrients and are likely to make you weak and sick, and the “Suspect foods” in yellow have a meaningful amount of toxins, but some nutrients too – they’re okay for some people, and cause problems for others. You don’t know until you eliminate the suspects!

Kryptonite foods are never a good choice unless you’re starving because they have few upsides and a lot of downsides. But even Bulletproof foods or Suspect foods from the roadmap vary in quality. Manufacturers have a lot of tricks up their sleeves when it comes to labeling, and many of them include harmful food additives marketed under harmless-sounding names. On top of that, man-made and natural toxins may contaminate some foods that appear Bulletproof at first glance.

What’s a Bulletproof reader to do?

The first thing is to recognize that fearing toxins won’t help you.

You could argue that fear itself acts as a “toxin” because it has such a strong negative effect on your biology. So accept the fact that the world has toxins, your body can deal with some toxins better than others, and it’s in your best interest to intelligently lower your exposure when you can. When you do take a hit from toxins, focus on recovering quickly.

Stress from mild exposure to some toxins can actually help you – the “what doesn’t kill me makes me stronger” argument. This phenomenon is called hormesis. Often, though, you get enough stress from work, exercise, and home life, and you’re better off avoiding toxins altogether.

This article shows you the most common additives and toxins that even a mindful foodie might encounter. It skips over issues with many kryptonite foods, because while there are certainly additives in mass-produced white bread, the Bulletproof Diet Roadmap already suggests that you avoid white bread. Learning yet another reason to keep it out of your diet doesn’t really help you.

But what if you’re looking for the most Bulletproof bacon around? Or choosing between two brands of coconut milk? The following food additives and toxins are common, even in foods that appear to be Bulletproof.

1) “Natural Flavors”

The FDA’s definition of “natural flavor” is exceptionally broad. From its website [1]:

“The term natural flavor or natural flavoring means the essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating or enzymolysis, which contains the flavoring constituents derived from a spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, bark, bud, root, leaf or similar plant material, meat, seafood, poultry, eggs, dairy products, or fermentation products thereof, whose significant function in food is flavoring rather than nutritional.”

Manufacturers can use the “natural flavor” label to hide hundreds of questionable ingredients. For example, autolyzed yeast extract is flavoring derived from edible yeast, and is therefore classified as a “natural flavor,” but it contains free glutamic acid that rapidly converts to the infamous flavor enhancer monosodium glutamate (MSG) in the body [2]. Sneaky, sneaky manufacturers.

“Natural flavors” covers a vast number of additives. Why take the chance? It’s better to know exactly what your food contains, and unless you really trust the company producing the product, it’s probably best to avoid anything with “natural flavors” on the ingredients list.

That said, I use “natural flavors” in FATwater™. They’re derived from fruit and vegetables essences. (I triple checked before I even tasted them during development!)

2) and 3) Nitrates & Nitrites

Nitrates and nitrites are common in cured meats (that includes bacon). They keep meat pink and extend its shelf life. They also keep bacteria and fungi at bay.

Nitrates and nitrites are unusual because they can go one of two ways: if you cook them at low heat and you have a healthy gut they’re great for you. Your body converts them to nitric oxide, a beneficial compound that studies suggest may decrease risk of heart attack, stroke, inflammation, and high blood pressure [3]. And you *want* nitric oxide for erectile function…

On the other hand, cooking nitrates and nitrites at high heat with protein or another amino acid source (pan-frying bacon until crispy or char grilling, for example) creates nitrosamines, potent carcinogens that studies have implicated in cancer formation in over 40 animal species [4,5,6].

Nitrosamines were first strongly linked with cancer in the ‘70s. Since then the FDA has required companies that add sodium nitrate and/or sodium nitrite (aka celery extract)  to their products to also add vitamin C to prevent nitrosamines from forming. That makes foods safer now, but nitrosamine formation still happens, especially if you cook your meat crispy or char it on a grill. And the companies that sell “nitrate-free” bacon are usually hiding something – instead they use celery powder, which is very high in nitrites but lets them get around the labeling of nitrates.

The bottom line: whether it’s labeled nitrate-free or not, buy pastured bacon and cook it at low heat. Low, slow cooking can decrease nitrosamine content and promote valuable nitric oxide formation instead. I use a dash of sodium nitrite (pink curing salt, NOT pink Himalayan salt) when I cure my own bacon.

4) Mercury

Mercury (think the stuff in old glass thermometers) is a toxic heavy metal that builds up in cells, especially in your brain/nervous system and liver. Mercury isn’t a food additive per se, but humans have inadvertently added it to a lot of seafood by polluting the ocean through burning coal.

A general rule of thumb is that the higher up on the food chain the fish you’re eating, the more mercury it contains. Sharks, for example, eat thousands of smaller fish during their lifetimes, and they accumulate the mercury that was in those smaller fish. As a result, shark steak is one of the most mercury-contaminated foods around. Plus, it’s mean to eat sharks. Shark fin soup has caused a sharp spike in overfishing, and unethical fishermen are capturing sharks, cutting off the fins, and dumping them still-living back in the ocean.

Another important factor at play in mercury content is selenium. One reason mercury is so bad for you is it deactivates selenium-related enzymes that, when functioning, repair and protect your brain from oxidative stress [7]. That said, when selenium and mercury bind together mercury also becomes inactive, leaving it less harmful [8]. That means as long as you (or the fish you eat) have more selenium in your system than you do mercury, mercury is likely less of an issue.

Unfortunately, selenium-to-mercury ratios vary widely, even in seafood the EPA and FDA consider low-risk [9, 10].

Here are two ways to hack mercury exposure:

  • Eat fish with low mercury and high selenium. Wild-caught Alaskan salmon is the golden example, especially sockeye salmon. It’s high in omega-3s and selenium and consistently lower in mercury than Coho and Chinook salmon are [11, 12]. Anchovies and sardines are also typically low in mercury. Be sure all your fish is wild-caught; farm-raised seafood is the marine equivalent of factory-farmed meat.
  • Get plenty of selenium, especially if you eat seafood regularly. On top of protecting you from mercury, selenium promotes balanced hormone levels and thyroid function [13]. It also protects your brain from oxidative damage [14]. You can take a supplement, or you can get your selenium from dietary sources like sockeye salmon, grass-fed beef, broccoli, cabbage, and spinach. Another popular source of selenium is Brazil nuts but they’re susceptible to mold, they accumulate other toxic metals, and selenium levels vary widely, so be cautious with them.

5) Roundup/glyphosate

Monsanto (the company behind big farming and many GMOs) created Roundup in the 1970s and began using it as a commercial herbicide. Roundup’s active ingredient is glyphosate, a chemical that improves margins for chemical companies by allowing them to sell genetically modified “Roundup Ready” seeds.

Glyphosate research is messy. Many studies suggest that glyphosate is safe. For example, a 2012 analysis of 21 glyphosate-related studies concluded that glyphosate did not correlate with cancer in humans [15]. On the other hand, another study conducted a year later found that glyphosate exposure doubled the risk of non-Hodgkin lymphoma in farmers and agricultural workers [16]. You can probably guess who funded many of the studies saying it’s safe.

There’s also evidence that glyphosate may inhibit beneficial gut bacteria [17,18]. Three of the strains it damages are reduced in children with gluten sensitivity [19], suggesting that glyphosate may contribute to the recent increase in gluten sensitivity in America.

Given that glyphosate acts on bacteria, which are required for healthy soil, it’s a bad idea to spray millions of pounds of it on our soil. The microbes in our soil ultimately dictate which will grow in our guts.

Pseudomonas aeruginosa, a damaging gut microbe, can use glyphosate as fuel and grow out of control, increasing risk of bacterial infection [20]. If that weren’t enough, when Pseudomonas aeruginosa processes glyphosate a byproduct of the reaction is formaldehyde, a potent toxin [21].

Is glyphosate safe? There plenty of evidence that you should avoid it if you want to live a long and healthy life, and that we should reduce our use of it in our crops if we want our soil – and humans – to stay fertile. Stick to organic produce, especially if the produce has a high pesticide load (you can check this list from the Environmental Working Group for pesticide ratings).

6) Arsenic

Arsenic is a toxin present in soil and water. Many plants absorb it to varying degrees. Arsenic exposure in humans has been linked to skin, liver, lung, bladder, and kidney cancer [22]

Rice plants are particularly adept at absorbing arsenic from the soil, and a number of the countries that export rice have recently had issues with arsenic contamination, Including China, India, and Bangladesh [23,24,25]. The type of rice matters, too: a recent FDA-run study found that brown rice, whole grain/wild rice, rice pasta, and parboiled rice had the most arsenic [26].

There are a few ways to hack arsenic content in rice:

  • Stick with white rice. It has less arsenic than its whole grain counterparts [26], and fewer antinutrients and inflammatory compounds as well. That’s why white rice ranks so high on the Bulletproof Diet Roadmap. It’s a good, clean source of carbs (and cooking it with coconut oil seems to decrease its glycemic index).
  • Wash your rice until the water runs clear before cooking it. Washing rice can remove a significant portion of the arsenic (28%, according to one study) [27].
  • Cook your rice with extra water and discard the excess water after the rice is cooked. Rice cooked at a 6:1 water:rice ratio reduced total arsenic by about 35% in one study [28], and up to 57% in another study, when combined with a preliminary wash [27].

Are there any harmless food additives?

Definitely. Some food additives get a bad rap because they’re made in a lab or have odd names, but not all additives are toxic. In fact, some of them are good for you. A few examples:

  • Guar gum is a thickening agent often found in coconut milk. It can cause gas and bloating in a minority of people, particularly those with small intestinal bacterial overgrowth (SIBO). For most people, though, guar gum is fine. In fact, studies show that guar gum can lower blood sugar levels after a carb-heavy meal in both rats and people, provided it’s unpasteurized [29,30,31].
  • Ascorbic acid is a scarier way to say vitamin C. It’s often used as a preservative because it’s such a strong antioxidant. Ascorbic acid not only doesn’t harm you – its great for you, and it’s one of the most effective forms if you want to supplement with vitamin C.  It even helps to stop nitrosamine formation.
  • Citric acid is an antioxidant derived from citrus fruits. It’s used in many cleaning products, as well as in food for preservative purposes or as a sour flavoring agent. Citric acid is beneficial for most people. One potential problem: some citric acid is derived from the fungus Aspergillus, which means particularly mold-sensitive people may react to it.
  • Alpha tocopherol is just vitamin E. Same deal as the two above – it’s another antioxidant preservative with a chemical-sounding name.

A quick word: it can be frustrating to think about toxins all the time. It’s great to get in the habit of checking labels and protecting yourself from common additives and toxins, but there’s a point where it can stress you out more than it’s worth.

If you’re at a Japanese restaurant with friends and you start asking yourself whether the salmon sashimi you’re about to eat is high in mercury…relax! A major strength of the Bulletproof Diet is that it boosts your resilience and primes you to handle the occasional toxin. In the case of the sashimi, you probably have enough selenium from all the grass-fed meat you eat that you can stand up to a dose of mercury without flinching.

In other words, if you eat along the Bulletproof Diet, odds are your body is well fed, your immune system is revving, and you’re equipped to deal with the occasional contaminant. Be as vigilant as you want, but don’t worry if you aren’t perfect 100% of the time. You’re building a resilient, ass-kicking machine. But there’s no reason to smack yourself over the head with a toxin when you have a better choice.

Any thoughts? Are there other toxins or additives that you look out for? Leave it in the comments, and stay Bulletproof!