Chapter 40
Fat Oxidation
More sulforaphane is needed
If you add acid to raw cruciferous vegetables, it can increase sulforaphane formation. For example, if you dress coleslaw with lemon juice, that can help a little, but vinegar is even better, presumably because of its higher acid content. But when cooking cabbage, the opposite could apply. Cooked red cabbage should stay blue, not turn purple, because that indicates an alkaline environment, which helps keep the important cruciferous components from breaking down (see see.nf/cabbageph). The decisive factor in cooking, however, is the pause between chopping and heating. I show my “Hack and hold” strategy in my cruciferous chapter in How Not to Die and in my video see.nf/hackandhold.
Fat Oxidation
We know that some foods act as antioxidants, while others, on balance, are pro-oxidants. Just as the Dietary Inflammatory Index is supposed to weigh the balance between anti- and proinflammatory foods, more than 20 systems have now been developed to assess oxidative balance. In general, the risk of heart disease and kidney disease, of getting cancer and dying from it, and of all other causes of death combined is higher the further the scale tips toward the pro-oxidant side. Although the ranking systems differ, they all agree that exercise, cruciferous vegetables, and certain components of whole plant foods such as fiber and carotenoid phytonutrients are net antioxidants that wipe out free radicals, whereas meat, alcohol, fat, and, for example, smoking are pro-oxidants that generate free radicals. In this regard, the greatest evil among dietary pro-oxidants is saturated fats.
Heterocyclic amines, the carcinogenic components that form when meat is heated or tobacco is smoked, can lead to the formation of free radicals, but that is not the only reason why meat and meat products contribute to oxidative stress. Our stomach behaves like a “bioreactor,” in which the heme proteins from blood and muscles oxidize fat in the acid bath. Chickens, for example, are only half bled out at slaughter, and the residue can drive fat oxidation so strongly that some industry representatives are advocating additionally decapitating the animals.
When we consume this oxidized (rancid) fat, it can penetrate into our LDL cholesterol particles and accelerate atherosclerosis, the stiffening of the arteries that ultimately is our leading cause of death. The amount of oxidized fat in the body can double within four days if you eat grilled turkey cutlets every day. (However, the harmful effects can be mitigated if you eat berries with meat meals. See the chapter on berries.) That may explain why vegetarians have hardly any cardiovascular disease, but oxidized fats also form when you heat plant oils. It is therefore not surprising that higher consumption of ultraprocessed junk food causes more DNA damage than eating only a small amount of it. But because of the “feared oxysterols,” oxidation of animal fats could be even worse.
Antioxidant Status of Vegetarians
Both systematic and nonsystematic reviews have concluded that plant-based diets protect against damage from free radicals, which “may explain why vegetarians live longer.” Most studies show that vegetarians, for example, suffer from less oxidative stress, but some see no significant difference compared with meat eaters or fish eaters, or even higher levels in vegetarians. As I lay out in detail in see.nf/antioxveg, the discrepant findings could be due to inadequate vitamin B12 intake among vegetarians and vegans who do not supplement their diet with B12 or foods fortified with it, since even a subclinical (symptom-free) B12 deficiency is associated with increased oxidative stress. A regular, reliable intake of vitamin B12 is crucial if you want to enjoy the full benefits of a healthy, plant-based diet.
Evil COPs
Too much cholesterol in the blood has long been seen as a primary risk factor for Alzheimer’s. Although cholesterol cannot directly cross the blood-brain barrier, cholesterol oxidation products (COPs) can. Oxysterols, oxidized cholesterol, are present in the blood and accumulate in the brain, where they are a driving force behind the development of Alzheimer’s disease. I present the chain of evidence for this in my video see.nf/copdementia.
COPs can be up to 100 times more toxic than unoxidized cholesterol. They may contribute to a broad spectrum of age-related diseases, including atherosclerosis, cataracts, kidney failure, osteoporosis, and cancer. That is why egg consumption and dietary cholesterol are generally associated with an increased risk of breast cancer. The most important byproduct of cholesterol oxidation in the blood, 27-hydroxycholesterol, has an estrogen-like effect and increases the proliferation rate of most breast cancer cells—sometimes even despite estrogen-blocking drugs.
How can we reduce the amount of oxidized cholesterol in our blood? Since oxidized cholesterol in the diet is a source of oxidized cholesterol in the blood, one way is not to eat it. Hours after consumption, the amount of oxidized cholesterol in the blood rises and circulates there for longer than six and even eight hours after a meal. Oxidized cholesterol is found in milk powder, meat and meat products (including fish), cheese, eggs, and egg products such as the egg powder in many industrial foods. Fresh, raw meat may start out with zero oxidized cholesterol, but heating or storage can drive it up dramatically. Any type of preparation can cause this, since maximum cholesterol oxidation is reached at about 150 degrees Celsius, but some are worse than others. For details, see my video see.nf/stopcops.
In general, the cholesterol in white meat, because of its higher content of polyunsaturated fat, is more susceptible to oxidation than that in red meat. Fish is usually the worst, followed by poultry, pork, and beef. Chicken has about twice as much oxidized cholesterol as beef, even before it is irradiated. If chicken is irradiated to make it safer with regard to infectious diseases, it could become more concerning with respect to chronic diseases because of its cholesterol oxidation.
Oxidized cholesterol exposure is supposedly “unavoidable,” but let’s take a step back. Only foods that contain cholesterol to begin with can produce oxidized cholesterol. The best method to prevent dietary intake is to reduce the total cholesterol content of your foods, meaning focusing on unprocessed plant foods that have no cholesterol that could be oxidized.
A Mystery Is Solved
Until relatively recently, our knowledge about oxidized cholesterol in the diet was limited, because there were not yet any test methods and techniques to accurately determine the amount in different foods. Although oxidized cholesterol has been found in all animal products, the amount in canned tuna is astonishingly high, 15 times higher than, for example, in beef or pork chops, but ghee takes the cake.
Ghee, clarified butter, is common in Indian cuisine. The heating by which it is produced apparently increases the amount of oxidized cholesterol tenfold. This much oxidized cholesterol in the diet may explain why the Indian subcontinent is so enormously affected by heart disease, even though a significant portion of the population avoids meat and eggs. In India, desserts made from dairy products are also prepared in a similar way.