Why You Should Eat Brightly Colored Fruits and Vegetables

by MARK'S DAILY APPLE


(Be sure to watch the video in which Terry Wahls explains how eating a Paleo diet rich in leafy greens, cruciferous vegetables, and brightly colored produce (plus meat and seaweed and fish and offal) coincided with a regression in her rapidly-progressing MS. Then, read the previous two installments on leafy greens and crucifers to get completely caught up.)

You know how those deep red beets sliced in half to show off the insides, those taut blueberries, those purple and violet mottled, oddly-shaped heirloom tomatoes lightly dusted with soil, and those glistening blackberries sitting in your periphery pop out and draw your gaze as you make your way through the farmers’ market? That’s not just clever product placement. It’s actually because of the pretty colors. It’s innate. It’s by “design.” Mother nature, you see, is a masterful visual merchandiser who comes up with all these lovely colors so that plants can reproduce. But wait – how does color help plants reproduce?

Simple. Plants tend to be stationary. Except for the ents, they are, quite literally, rooted in place. A tomato plant can’t walk, can’t kneel and lovingly place its firstborn into a shallow womb dug into the soft, fertile earth. That would be awesome to see, but it’s not gonna happen. What does happen is that colorful plants catch the eye of hungry organisms who eat the fruit, swallow the seed, and poop it out someplace else, thus giving it a chance to take hold, germinate, and develop into a full-blown adult plant. In order to disseminate their progeny across the land, many plants must therefore manufacture pigments – colorful compounds that draw the eye and signal “food source” to mobile, hungry organisms. Being mobile, hungry organisms ourselves, we are also attracted to colorful fruits and vegetables.

And for good reason. See, mother nature is also thrifty. It’s rare that she manufactures a compound with only one use – she likes her creations to multitask – and plant pigments are no different. They serve multiple roles in plants in addition to attracting animals, such as protecting it from UV damage, dampening the effects of excess light, enabling photosynthesis, and even acting as endogenous antioxidants (plants can’t really sip red wine and pop supplements, after all). Luckily, it appears that we can leverage many of these pigments for our own gain by eating brightly colored fruits and vegetables.

Which is why both Terry Wahls and I recommend eating a wide variety of them. There are hundreds of different bioactive plant pigments, each with unique effects. Rather than isolate just one or two, by eating a variety of colorful plants we ensure consumption of a wide range of potentially health-promoting plant pigments.

I could end this post now with the basic advice to “eat colorful foods and lots of them.” This would cut down on reading time, ingratiate myself to vegan and vegetarian readers, and still manage to convey an effective, actionable message. But alas, I know you guys like the gritty details. It’s not enough (for most of you) to read someone tell you that eating blueberries and purple sweet potatoes is healthy. Sometimes you want to vividly imagine those anthocyanins sliding down your gullet, preventing the oxidation of omega-3 fatty acids in your gut, and interacting with your body at the cellular level to produce beneficial antioxidant and/or hormetic effects. Sometimes you want to know what you’re putting inside your body on a deeper level. If that’s you, keep on reading. If it’s not, just go out, eat some colorful produce, and you’ll be fine.

When I put this post together, I struggled with formatting. Should I cover each individual pigment? With dozens of them out there, that would be a large undertaking. Should I cover each plant? Plants contain multiple pigments, so it could get confusing rather quickly. Should I cover each color? That’s confusing, because there’s a lot of overlapping and combinations of different pigments into different colors. I decided to break them up into pigment categories.

Anthocyanins and Other Flavonoids

Since I already mentioned anthocyanins, let’s start there. Anthocyanins are flavonoids, the most common type of polyphenol. Pretty much any fruit, vegetable, or flower with a significant amount of purple or blue gets that color from anthocyanins. Even some reds can be anthocyanin-based. The deeper the color, the more anthocyanins. We’re talking:Blueberries – Anthocyanin-rich blueberry juice improved cognitive function and memory in aging adult humans.

Raspberries (black and red) – Raspberry juice shows anti-atherosclerotic effects in hyperlipidemic rodents, and although human studies are lacking, there is a strong basis for considering them a healthful food.

Blackberries – Perhaps my favorite berry, blackberries are rich in flavonoid pigments with in vivo evidence of protection against neurological degeneration and bone loss.

Purple sweet potatoes – Tons of references in my sweet potato post (that’s my post about sweet potatoes, not my sweet post about potatoes). Same goes for regular purple potatoes.

Eggplants – Nasunin, a potent eggplant anthocyanin that is strongly absorbed in the GI tract, displays antioxidant effects. Make sure to eat the peel, though.

Cherries – Although (again) human studies are lacking, the considerable anthocyanin content of cherries suggests that their efficacy in animal models may well carry over to us.

Cranberries – Cranberry juice, whose anthocyanins are bioavailable in humans after drinking, improved vascular function in heart disease patients.

Purple tomatoes – In addition to carotenoids (more on those below), purple tomatoes also contain significant levels of anthocyanins.

Purple carrots – Same goes for purple carrots.

There are even vegetables that have feet (roots?) both in the colorful camp and the sulfur-rich or leafy-green camps. Like:

Red leaf lettuce – Leafy green and colorful.

Radicchio – Leafy green and colorful.

Red cabbage – Sulfur-rich and colorful (with 36 different anthocyanins).

Purple cauliflower – Sulfur-rich and colorful.

Purple kale – Leafy green, sulfur-rich, and colorful.

I could go on, but I won’t. The point is that any plant with these colors is going to contain these compounds, because these compounds literally are the colors. That means I’ve missed the vast majority of anthocyanin sources, but it also means that you’ll have an easy time finding them out there in the world. Eat up (but rinse your mouth out after; they stain) and go for blues, reds, and purples.

Oh, yeah. There are a couple other relevant flavonoids. Anthocyanins get the most press, but there are other foods with potentially beneficial health effects due to flavonoid content.

Turmeric – Contains curcumin, which gives the spice its distinctive, persistent yellow color. I’ve written an entire piece on the health benefits of turmeric, and curcumin is responsible for the lion’s share of them.

Apples and onions – A light yellow pigment, quercetin is found in apples and onions (except for white onions). Red and yellow onions are high in quercetin (PDF), while most of the quercetin in apples resides in the skin.

Carotenoids


Carotenoids are pigments that provide the orange, yellow, and red colors found in foods like carrots (get it?), sweet potatoes, cantaloupes, bell peppers, squash, watermelon and tomatoes. You’ve got beta-carotene, alpha-carotene, beta-cryptoxanthin, gamma-carotene, and beta-zeacarotene, which can be partially converted to retinol, the active (animal) form of vitamin A. You’ve also got lutein, lycopene, and zeaxanthin, which cannot be converted to vitamin A.

Don’t rely on carotenoids to fulfill your vitamin A requirements. Liver and egg yolks are much better, more reliable sources. Besides, beta-carotene supplementation doesn’t seem to work very well. In several studies, it has appeared to increase the risk of lung and prostate cancer, and a 2007 Cochrane review found that beta-carotene supplements were associated with an increase in general mortality. “Supplementation” of alpha-carotene, via carotenoid-rich fruits and vegetables, however, appears to have the opposite relationship. Huh, food’s good for you… who knew?

Get carotenes through orange vegetables and fruits, like squash, carrots, sweet potatoes, cantaloupes, and bell peppers.

The other carotenoids – the ones that don’t convert to vitamin A, like lutein, lycopene, and zeaxanthin – appear to be helpful. Both lutein and zeaxanthin accumulate in the retinas of our eyes, where they seem to play major roles. The more lutein and zeaxanthin you eat, the more it accumulates in your retina (although this is most pronounced in patients with low baseline pigment levels). Low dietary intake of lutein and zeaxanthin are associated with elevated incidences of age-related macular degeneration, and a similar relationship was found for cataracts.

Get lutein and zeaxanthin through spinach, kale (what doesn’t kale have?), dandelion greens, chard, collards, romaine lettuce, paprika, and turnip greens.

Lycopene does some cool stuff, too. It reduces lipid peroxidation in people with heart disease, as well as protects the skin against UV-related damage from the sun. There’s also a lot of research into the effect of lycopene intake on cancer, particularly prostate cancer.

The best sources of lycopene are cooked tomato products, like tomato paste or sauce, especially cooked with fat (but not sunflower oil!), but lower levels can be attained through raw tomatoes, pink grapefruit, pink guava, and watermelon. The absolute best source, however, is gac, a Vietnamese fruit that beats tomatoes by 70-fold. It also contains high levels of other carotenoids, all of which are bound by long chain fats, making them even more bioavailable. Anyone every try gac?

Betalains

Although betalain pigments are described as “deep red” and “purple” and sound similar to the anthocyanin family, they are not the same. They look different (just compare a beet to a strawberry – not quite the same). In fact, betalains and anthocyanins have never been found in the same plant; they appear to be mutually exclusive. Besides the beet (where “betalain” gets its name), rhubarb, and the stems of chard, there aren’t very many sources of readily edible betalains. I suppose you could throw together a floral salad of bougainvillea, amaranth, and purple cacti, but for the most part, you’re going to get your betalains from beets.

All beets contain all betalains, just in different ratios. In purple or red beets, betacyanins predominate. In yellow beets, betaxanthins predominate.

Possible benefits of betalains include:

Inhibition of lipid peroxidation.

A beet extract rich in betacyanins showed cytotoxic effects on human prostate and breast cancer lines.

Betacyanins from red beets protected gamma-irradiated mice.

Well, I hope that’s enough to convince you to include more color in your diet. As you can see, not all of the benefits of plant pigments are “proven,” but they’re probably all quite safe in the amounts you’ll find in foods. So go ahead and eat up a wide variety. If they do turn out to be helpful, you’ll have hedged your bet quite nicely.

USDA's New Symbol of Dietary Guide is Propaganda for Dairy Industry

While there's some good news when it comes to fruit and vegetables, the new guidelines seem tailored to encourage maximum dairy industry profitability. 

By Ari LeVaux, AlterNet
Posted on June 13, 2011

MyPlate, the USDA's new symbol of dietary correctness, was unveiled on June 2. It replaces the agency's Eating Right Pyramid (est. 1992), which succeeded the Four Basic Food Groups (1956). Those four in turn represented a consolidation of the seven food groups the agency pushed in the 1940s, themselves pared down from 12 during the Great Depression, when many people would have been happy to find even a single food group on their plates.

The USDA's first nutrition guide was published in 1916, a year after the National Dairy Council was founded. The dairy industry has worked tirelessly with (and on) the USDA ever since -- an investment that has paid many dividends, including dairy's privileged perch as one of only four basic food groups. And despite zero scientific basis that a healthy diet requires dairy, the stuff has managed to maintain its position as a key dietary recommendation on each successive symbol du jour, through the pyramid days and on to today's MyPlate graphic.

In fact, the MyPlate paradigm is practically a repeat of the Four Food Groups, with only three discernible tweaks.

The "meat and fish" group has been generalized to "protein." This is barely even a change, and more of a semantic adjustment to reality given how many ways there are to get your fill of essential amino acids without meat.

The grain group made the transition from to MyPlate relatively unscathed, with an added piece of advice to eat more whole grains. It's worth mentioning that plenty of "Paleo diet" followers, not to mention the Atkins crowd, seem to do fine without grains as well. And if you avoid grains and sugars, it's practically impossible to get fat.

The most substantial change to the dietary recommendations is the "fruit and vegetable" category, which has been split in two. Fully half of the USDA's new plate consists of fruit and vegetables. This is an audacious goal considering how few Americans currently come close to consuming that ratio. If taken to heart by enough people, this change alone could have profound effects on public health.

By including recommendations against oversized portions, and generalizing the protein group, the USDA has managed to distance itself from the influence of special interests like the meat and fast-food industries. But it remains clearly beholden to dairy.  

This brings us to the third discernible difference from the four food groups: the MyPlate symbol includes a little circle next to the plate that looks like a glass of milk. Labeled "Dairy," it stands for three daily servings of dairy, including cheese, yogurt, milk, and other processed secretions of mammary glands, usually bovine.

In response to MyPlate's debut the dairy industry took a victory lap, with press releases from various dairy-oriented think tanks and trade groups praising the new symbol.

"USDA's new MyPlate, the simple visual metaphor of a serving of dairy products alongside a plate, says it's vital to consume three servings of low-fat and fat-free dairy foods every day," gloated Jerry Kozak, president of the National Milk Producers Federation, as he tacitly reveals how the new guidelines seem tailored to encourage maximum dairy industry profitability.

Three servings of dairy per day would be an increase for most Americans, who currently consume an average of two. Encouraging Americans to eat low-fat and nonfat milk products means even more profit, because the fat skimmed off is then processed into butter and other marketable products. The more items you can sell from a single gallon of milk, the more money you make, which is why as far as the dairy industry is concerned the MyPlate cup might as well be full of champagne: the industry has convinced USDA to recommend increased consumption of a product that's not only unnecessary, but is actually bad for most people.

Lactose intolerance, by some estimates, affects 75 percent of the world's population.

Caucasians have one of the lowest rates of intolerance, at only 12 percent. These numbers don't include the people like me, who may not get explosive diarrhea and other classic effects of lactose intolerance, but don't do well on dairy, with results including phlegm, heartburn and upset stomach. And if 75 percent or more of the world's humans can't handle dairy, it's hard to argue it being necessary for optimal human health.

Here is USDA's obsequiously dairy-centric advice to the lactose-averse: "If you avoid milk because of lactose intolerance, the most reliable way to get the health benefits of dairy products is to choose lactose-free alternatives within the Dairy Group, such as cheese, yogurt, lactose-free milk, or calcium-fortified soymilk (soy beverage), or to consume the enzyme lactase before consuming milk."

Calcium is the primary justification for the importance of dairy, but many green vegetables offer just as much calcium as milk, and in a more easily absorbed form. With the exception of soymilk, all other calcium sources, including almond milk -- which contains twice the calcium of dairy milk -- are cautioned against:

"[Non-soy, non-dairy calcium sources] may provide calcium, but may not provide the other nutrients found in dairy products."

If science and health were calling the shots, then milk products would simply be absorbed into the protein category as one of many ways to get your essential amino acids, or perhaps into a "calcium" group that would also include dark-green leafy vegetables and fortified dairy alternatives.

Much of the positive health hype about dairy is perpetuated by the National Dairy Council, which has a history of exaggerating dairy's positives and downplaying its negatives. In 2007 the Federal Trade Commission forced the NDC to retract its claim that dairy consumption encourages weight loss.

The NDC is "the nutrition research, education and communications arm of Dairy Management Inc," the Web site of which makes its intentions clear -- and improving public health isn't one of them. "DMI helps build demand for dairy on behalf of dairy producers and is dedicated to the success of the dairy industry."

Consuming dairy products is a choice that we (at least the lactose tolerant among us) have. But to spin the consumption of milk as a thrice-daily necessity is yet another scary reminder of the power that industries wield on policy.

At least with food we have the option to think for ourselves. But if USDA policy is so clearly shaped by industry, it makes you wonder about compromises the agency might make in other areas of its purview. USDA regularly makes decisions on things like pesticide regulation, forest policy and approval or disapproval of genetically modified crops. And those decisions, unlike a plate symbol, aren't so easily ignored.