Everything You’ve Always Wanted to Know About Antioxidants

Today, the awesome power of antioxidants. And, we start with an investigation into which bean, berry, and lentil has the highest antioxidant effect.

An apple a day has been associated with as much as a 35 percent lower risk of premature death. But which apple is best? Whichever apple you’ll eat the most. So, eat your favorite apple. But if you don’t care which apple you eat, or you’re just curious, which apple has the highest antioxidant content: Fuji, Gala, Golden Delicious, Granny Smith, Pink Lady, or Red Delicious? Granny gets the gold, with more than twice as many antioxidants as Golden Delicious apples.

Interestingly, antioxidant content roughly corresponds with the ability to lower cholesterol levels within one month for those randomized to eat an apple a day. Annurca apples beat Granny Smith, but presumably it’s because study participants got two Annurcas a day, versus just one of the others, because they were about half the size. But two apples, even when they’re half the size, have more overall surface area, and the magic may be in the peel. If you randomize people to eat apples with or without the peel, you see a significant boost in artery function within an hour of peel consumption. So, don’t peel your apples.

For other foods, the antioxidant spread can be even greater. Check out nuts. Walnuts for the win! Followed by pecans, then pistachios, and who would have guessed almonds would be way down at the bottom?

Walnuts also have the highest omega-3 content, by a large margin, beating out other nuts in suppressing the growth of cancer cells in a petri dish. And, walnuts are the only nuts shown to markedly improve human artery function.

Blackberries beat out blueberries for antioxidant capacity.

The beans surprised me. What do you think fits the bill for best bean, at least from an antioxidant perspective? Want to pause it and take bets?

The lowest on the leaderboard…chickpeas. Holy hummus! The mightiest free radical fighter is the fava bean, with kidneys and pintos neck and neck for number two.

Lentils were another big surprise. I would have guessed black or red lentils to be up there, with brown or green at the bottom. But check this out. Green lentils have about four times the antioxidant power of red ones!

Next up, how antioxidants may lower the risk of depression.

According to the latest from the CDC, the rates of all of our top ten killers have fallen or stabilized except for one: suicide. Accumulating evidence indicates that oxidative free radicals may play important roles in the development of various neuropsychiatric disorders, including major depression.

For example, in a study of nearly 300,000 Canadians, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders, and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in antioxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that was just based on asking how many fruits and veggies people ate. If you measure the levels of carotenoid phytonutrients in nearly 2,000 people across the country, a higher total blood carotenoid level was associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes, but also present in watermelon, pink grapefruit, guava, and papaya, is the most powerful antioxidant amongst the carotenoid family. In a test tube, it’s about 100 times more effective at quenching these free radicals than vitamin E, for example.

And in a study of about a thousand older men and women, those who ate the most tomato products had about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher intake of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it’s the antioxidants, can’t we just take an antioxidant pill? No; only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial, and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants at all, but rather to other dietary factors, such as folate, which also occur in fruits, vegetables, and plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been getting enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn’t know if the low folate led to depression, or the depression led to low folate. Maybe when you have the blues, you don’t want to eat the greens.

But since then, a number of cohort studies were published following people over time, and low dietary intake of folate may indeed be a risk factor for severe depression–as much as a threefold higher risk. Note this is dietary folate intake, not folic acid supplements; so, they were actually eating healthy foods. If you give people folic acid pills, they don’t seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements, because it’s more shelf-stable, but it may have different effects on the body, as I explored previously.

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high-dose vitamin C, also known as ascorbic acid. The vitamin C, but not placebo, group experienced a decrease in depression scores, and also greater FSI. What is FSI? FSI evidently stands for penile-vaginal intercourse, an acronym that makes no sense to me.

But evidently, high-dose vitamin C improves mood and intercourse frequency, but only in sexual partners who don’t live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, but with no big change on vitamin C. But for those not living together on vitamin C, every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one—some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency; so, it does not appear that the depression scores improved just because of the improved FSI.

Finally today, to stay out of oxidative debt, we need to take in more antioxidants than we use up.

“The postprandial state is a pro-oxidant state”—meaning that after each meal, free radicals are produced as our body assimilates the food. So, we can’t just have a bowl of berries in the morning to meet our minimum daily antioxidant needs, and call it a day. “[E]ach and every meal” should contain high-antioxidant foods, which, if you remember, means plants. “[A]ntioxidant-rich foods originate from the plant kingdom.” This is due to the thousands of natural antioxidant compounds found naturally in plant foods.

For example, “consuming…fruits,” which are high in phenolic phytonutrients, increases the antioxidant capacity of the blood. And, when they are consumed with the Standard American Diet, high-fat and refined carbohydrate “pro-oxidant and pro-inflammatory” meals, they may help counterbalance some of their negative effects. “Given the content and availability of fat and sugars in the Western diet, regular consumption of phenolic-rich foods, particularly in conjunction with meals, appears to be a prudent strategy to maintain oxidative balance and health.”

And, of all fruits, berries may be the best. Add a glass of red wine, which contains berry phytonutrients from grapes, and we can bring down the level of oxidation, but not blunt it completely. So, the meal needs even more plants.

In this study, they gave people standard breakfast items, resulting in lots of oxidized cholesterol in their bloodstream one, two, three, four, five, six hours after the meal. But, all it took was a cup of strawberries with that same breakfast to at least keep the meal from contributing to further oxidation. Note, though, without the strawberries, look where we’d be at lunchtime. Let’s say we ate a standard American breakfast at 6 am, if we didn’t eat that cup of strawberries with breakfast, by the time lunch rolls around, we’d already be starting out in a hyper-oxidized state and can just make things worse. “Since Western eating patterns include eating multiple meals a day, including snacks, one can only speculate on the level of biological unrest.”

But, at least if we had some berries for breakfast, we’d be starting out at baseline for lunch. “This acute protection is likely due to the antioxidant effects of the strawberry phytonutrients.”

Even better than baseline, how about our meal actually improving our antioxidant status? Here’s measuring the antioxidant level of one’s bloodstream after a crappy meal. It drops, using up our antioxidant stores. But, eat a big bunch of red grapes with the meal, and the antioxidant level of our bloodstream goes up, such that our body is in a positive antioxidant balance for a few hours. Same thing after enough blueberries. And, imagine if these ensuing hours between our next meal, right, we were sipping green tea, or hibiscus? We’d have this nice antioxidant surplus all day long.

What, according to the researchers, are the practical implications? “These data provide an interesting perspective for advising individuals on food choices when consuming a moderate- to high-fat meal is unavoidable.” Unavoidable? So, if we’re like locked in a fast food joint, or something? Well, then they suggest chasing whatever we’re forced to eat with some berries. Reminds me of those studies on smokers I talked about, suggesting those who smoke should eat lots of kale and broccoli to reduce the oxidative damage to their DNA—or, they could just not smoke.

“In a single day, the systemic stress of [all that fat in our blood] and redox imbalance [being in a mild pro-oxidant state after meals] may seem trivial. Over time, however, these daily insults can lead to complicated atherosclerosis,” contributing to hundreds of thousands of deaths a year.