Below is a basic eating philosophy based around minimizing oxidative stress. To learn more about oxidative stress, refer to the blog.
NUTRIENTS TO REDUCE OXIDATIVE STRESS
These should be prioritized, in no particular order:
High-quality protein (needed for synthesizing glutathione, which is essential for all antioxidant activity)
Manganese (required for superoxide dismutase, which reduces superoxide radicals)
Zinc (required for superoxide dismutase)
Copper (required for superoxide dismutase)
Iron (required for the catalase enzyme, which reduces hydrogen peroxide. Heme iron from animal sources is the most bioavailable form)
Selenium (required for glutathione peroxidase, which reduces hydrogen peroxide)
Vitamin E (needed to combat lipid peroxidation. Not much is needed if little polyunsaturated fat is consumed)
Vitamin C (required for recycling vitamin E)
Antioxidant-supporting phytochemicals (can directly reduce superoxide or upregulate overall antioxidant activity via hormesis)
B vitamins niacin and riboflavin (required for glutathione recycling)
Note that while protein can be safely eaten in abundance by most people, some vitamins and minerals require more careful balance. That means supplementing with them in high doses can result in negative side effects, so getting them from whole food sources is best.
BEST PROTEIN SOURCES
Animal foods are superior for obtaining high-quality protein and fat. Not only are they delicious, but they also contain a wide range of vitamins and minerals that support the antioxidant defense system. Meat, eggs, and dairy are all high in saturated and monounsaturated fats, which are highly resistant to lipid peroxidation. Fish are high in omega-3 polyunsaturated fats, which, unlike omega-6 polyunsaturated fats, have been shown to reduce lipid peroxidation and offer a plethora of other benefits, according to research.
Plant proteins are less bioavailable, do not contain all essential amino acids, and the foods containing them generally do not taste as good as animal foods. While there is nothing inherently wrong with plant protein, obtaining an abundance of high-quality protein from plant sources is more challenging. The amino acids glutamate, cysteine, and glycine are particularly important for glutathione synthesis, so those consuming protein primarily from plant sources will need to carefully manage their diet to ensure they are getting sufficient amounts.
BEST FAT SOURCES
As mentioned, many animal foods already naturally contain healthy fat. Some fruits, such as olives, avocados, and coconuts, are also nutrient-rich sources of fat. For cooking, tallow, butter, ghee, coconut oil, and palm oil should be most preferred for their low polyunsaturated fat content. Extra virgin olive oil of verifiable quality can be beneficial, as its polyphenols have been studied extensively for their antioxidant benefits, but it should not be heated because heat contributes to oxidation of the oil.
Oils derived from seeds should be avoided as much as possible. That means canola, soybean, sunflower, safflower, grapeseed, etc. Unlike fruit oils (olive, avocado, coconut, palm) that can be extracted from simple pressing, these oils require an extensive refining process to extract and are highly susceptible to oxidation, especially when heated. Unfortunately, they are used everywhere, which is why consumption of these “vegetable” oils in the US was estimated to be 749 calories per person per day on average as recently as 2021. That’s why cooking at home, avoiding ultraprocessed foods, and reading ingredients labels are all important strategies for avoiding seed oils.
Nuts contain useful minerals but have limited protein and a high concentration of omega-6 polyunsaturated fats. They also contain phytic acid and lectins, antinutrients that inhibit the absorption of calcium, iron, and zinc. This is because nuts are seeds, and from a naturalistic perspective, it makes sense for seeds to contain antinutrients to protect against predation. Unlike fruit, which plants produce to be eaten and to have their seeds dispersed, seeds like nuts are not meant to be consumed freely. However, nuts do provide some vitamin E, which helps counterbalance the oxidative effects of their omega-6 fats.
BEST CARBOHYDRATE SOURCES
Carbohydrates are non-essential in the human diet; however, many people, including myself, prefer to include them to optimize their health. Their consumption should be secondary to nutrient-rich animal foods, though the amount of carbohydrates consumed depends on individual preferences and needs. Some people thrive on zero carbohydrates, and that’s perfectly fine.
Fruit is delicious, nutrient-rich, and contains polyphenols, some of which can directly scavenge superoxide radicals (like flavonoids), while others can activate the transcription factor NRF2. This activation signals genes to upregulate the production of enzymes that facilitate antioxidant activity, such as glutamate-cysteine ligase. Raw honey contains only trace nutrients but is abundant in polyphenols that can scavenge superoxide and other free radicals. The types and quantity of polyphenols vary because honey depends on the types of flowers from which the bees have collected nectar. Darker honeys are typically higher in polyphenols.
Refined grains should be avoided in favor of whole grains, but all grains, because they are seeds, contain phytic acid and lectins. Furthermore, gluten increases gut permeability by reacting with a protein in the gut called zonulin, loosening the tight junctions and allowing bacterial remnants called lipopolysaccharides into the bloodstream. This leakage can trigger an immune response, which can contribute to oxidative stress because immune cells generate ROS to kill pathogens, and ROS from immune cells can potentially leak into surrounding tissue. Therefore, if grains are chosen as food, non-gluten-containing whole grains are probably better than gluten-containing whole grains. Moreover, homemade fermented sourdough has reduced gluten and antinutrient content, making it a healthier choice. Note that most store-bought breads in US stores are considered junk food, even many of the 100% whole grain breads (check the ingredients). The best store-bought bread by a wide margin is Ezekiel Bread, which can sometimes be found in freezer aisles due to its lack of preservatives.
Beans are an affordable and nutrient-rich source of carbohydrates, but, like grains, they are seeds and contain lectins and phytic acid. Soaking and cooking them can reduce the antinutrient content, while fermenting can reduce it even further. Overall, they are a solid source of nutrients that support antioxidant activity.
My overall ranking of carbohydrate sources is:
Fruit: Delicious and nutrient-rich. Often contains bioactive polyphenolic antioxidants.
Raw Honey: Extremely delicious and contains a high concentration of bioactive polyphenolic antioxidants, but lacks a significant amount of nutrients.
Root Vegetables: Potatoes, especially, are very nutritious but taste bland. Some potatoes and other root vegetables are high in oxalates, so people with oxalate issues may want to limit them.
Beans: A good source of nutrients when prepared properly; contains protein and is affordable, but can taste bland and cause digestive discomfort.
Fermented Whole-Grain Sourdough Bread: Tastes good and has some beneficial nutrients.
Non-Gluten-Containing Whole Grains: Tend to contain some beneficial nutrients but taste bland.
Gluten-Containing Whole Grains: Similar to non-gluten grains in nutrient content, but gluten may negatively impact the antioxidant system by increasing gut permeability.
Leafy Vegetables: Not enough calories, taste terrible on their own, and are hard to digest, but do not negatively impact health for most people. Useful for flavoring dishes and often contain bioactive polyphenolic antioxidants.
Refined Grains: Taste great but offer very few nutrient benefits.
Refined Sugars: Taste great but provide zero nutrient benefits.
I included taste as an important factor in the rankings because why eat foods that don’t taste good? This ranking order isn’t absolute, and different people might prefer different foods towards the top of the list. As for the amount of carbohydrates, it doesn’t matter because the total carbohydrate amount likely won’t impact antioxidant defense, so restricting carb amounts is not necessary, but also not harmful; the quality of carbs is more important than the quantity. Chris Masterjohn’s course on the antioxidant system delves into more detail about this.