The following is an excerpt from a longer email in which a reader expressed concern over the apparent scarcity of "perfect foods.":
Dear Mark,No food is perfect. You are correct. But you are incorrect to despair over this unavoidable, inescapable reality. For one, you have to eat something. You can't live on sunlight and water (although both are vital to health). Two, just because a food contains something "bad" doesn't mean the food itself is "bad." To show this, I thought it'd be fun to put together a list of the "downsides" of undoubtedly Primal foods that most of us probably consume on a regular basis. Within many of these Primal darlings lurks a dark side, a "negative" nutritive trait that threatens to topple its favored status... but are you going to stop eating these foods just because they aren't "perfect"?
I'm getting very frustrated. I don't know if it's a case of over researching things, but I'm beginning to feel that there are very few perfect foods. That there is something bad in everything. Beef, pork, and fish have creatine. Nuts, grains, seeds, and legumes have phytates. What are we supposed to do, just live on veggies, chicken, and eggs? How is it that Grok got enough magnesium, not too much phytates, etc, etc?
Liver - Awesome superfood nature's-vitamin status aside, it has a "problem." It's high in retinol, which is the animal form of vitamin A and the most easily-absorbed. Too little dietary retinol is bad for testosterone production, vision, bone metabolism, and gene transcription, but too much dietary retinol can lead to hypervitaminosis A, especially with insufficient vitamin D. Explorers who ate polar bear liver, which contains upwards of 15,000 IUs retinol per gram (an insanely high concentration), have been sickened and even killed from hypervitaminosis A (PDF).
Red meat - Protein, loads of healthy fats, plenty of zinc, what's not to love? Well, for those with hemachromatosis - excessive iron absorption - the iron content of red meat can be problematic.
Eggs - Eggs are great. They are bite-sized, easily-transportable, delicious repositories of everything you need to build a fully grown chicken, but they also contain potentially gut-irritating proteins (mostly in the egg white) that can exacerbate autoimmune conditions. Lysozyme appears to be the most problematic of these egg proteins, and it's found in large amounts in the white.
Butter - Good old butter. You've yet to fail anyone. Except for that guy with an intense casein intolerance.
Ghee - That means ghee is all clear, right? All of the good fat, none of the offensive proteins. Maybe not. An older study from 1987 found that ghee had a significant amount of oxidized cholesterol, presumably due to the clarification process (which involves heat). That sounds bad. So ghee's bad, right? Maybe not (again). It turns out that the ghee from the 1987 study was "heated in an electric oven in a stainless steel mug at 120 degrees C for 50 hours." So, while some ghee has "bad" qualities, some does not, and it all depends on how the ghee was produced.
Shellfish - Delicious, nutritious, briny, mineral-replete though they may be, shellfish can be highly allergenic in certain people. Also, because you're eating the entire animal, including that animal's last meal, often raw, there is an elevated risk of getting sick. Norwalk virus (not serious), vibro (pretty serious), and various shellfish toxins are all potential complications. I love raw oysters, mind you. I'm just putting this out there.
Brazil nuts - I recently mentioned these as a great source of selenium. And they are. But they're also pretty high in phytic acid and radium.
Spinach - I love spinach, always have. It's a great source of magnesium, calcium, manganese, vitamin K... and oxalates. Yes, oxalates - those tiny organic crystals that compose the most common type of kidney stone - are found in spinach (as well as other leafy greens). 100 grams of spinach contain 750 mg of oxalates. And though dietary oxalate has never been conclusively or strongly linked to the development of kidney stones, the theoretical risk remains.
Dark chocolate - It's evidently a big favorite among my readers, and it has tons of benefits, but it's also high in phytic acid, and some sources may be high in cadmium and/or mycotoxins (like aflatoxin).
Bacon - I don't think listing the benefits is necessary here, so I won't. How about the negatives? Pork fed on corn and soy (which even organic pigs usually eat) display high levels of omega-6 fats in their tissues, while pork fed on coconuts display almost none. If you're eating bacon (almost all fat) from pigs fed mostly corn and soy, you're likely consuming a fair bit of omega-6 (same goes for any high-fat pork product, really, as well as poultry). Oh, and don't burn that bacon, or subject it to high heat for very long unless you love eating carcinogenic nitrosamines with your eggs!
Cruciferous vegetables - I just posted an article extolling the virtues of sulfur-rich cruciferous veggies, but they can also act as goitrogenic inhibitors of thyroid function. Goitrogens interfere with iodine uptake by the thyroid, so excessive intake of cabbage, cauliflower, and other cruciferous vegetables might necessitate a bit more iodine in the diet.
My point, after all this, is not to keep you from eating these foods. It's to show that there are no perfect foods and that there's nothing wrong with that. Every food, even the "good" ones, has something that someone can legitimately complain about. Does that mean you can't eat these foods, or even that you should always keep the vitamin A content of grass-fed beef liver or the possibility that your square of dark chocolate could contain cadmium in the back of your mind? No; it would drive you insane and cause unnecessary stress.
I simply wanted to show the inherent silliness of worrying about "perfect foods." Every food has something "wrong" with it. As I've always said, it's not just about the constituent parts that compose a food. The individual components don't always tell the whole story. Whole foods do tell that story, though. You simply have to eat them to figure it out.
That's it for today, but what about you, dear reader? Do you worry about the dearth of "perfect foods"? Do you think any foods actually are perfect, after all? Leave your thoughts in the comment section. Thanks for reading!