Week 13: Phytonutrients - Nature's Unknown Soldiers
Look deep, deep into Nature, and you will then understand everything better.
Our favorite scientist/theoretician/paragon of genius, Albert Einstein, spent no time engaged directly in food or nutrition science, but many of his quotes belied a sensitivity toward - and appreciation for - Nature's unmatched holism. That term - holism - was coined by South African statesman and philosopher Jan Smuts, in his 1927 treatise, 'Holism and Evolution' - which he dashed out during that year's parliamentary recess. It championed a focus on systems rather than parts. The idea of studying isolated components of things has constituted the lingua franca of the scientific community since the onset of the modern scientific method - an attitude that is just now beginning to change in favor of the systemic inter-relationship of things that Smuts and Einstein saw as self-evident. The ur-example is Nature itself. It is utterly impossible to remove one element or aspect of its system without inducing a (usually harmful, often cataclysmic) domino effect, whether that element is a single food nutrient among hundreds, like the enzyme lactase in milk which, once pasteurized, is killed, severely reducing our ability to digest and absorb its lactose (more on this later); or like Yellowstone's wolves - whose 1995 re-introduction has led to the wholesale rejuvenation of not just myriad animal populations but of willow trees and rivers, not to mention everything that depends on them (more on that amazing story here).
Enter the phytonutrient - aka phytochemical.
Most of us now know that we need vitamins, minerals, fats, proteins, carbohydrates and even fiber in order to live. [If you're unclear on any of it, we welcome you to read our posts up to this point, starting with Week 1's overview.] But what nutritional science is just beginning to understand is that while these substances are indeed our bodies' fuel, it is another entire category of sub-nutrient that may be the glue that holds everything together, and catalyzes the processes that allow us to use nutrients. Like the concept of holism, a plant's phytonutrients have a large effect on the conversion, quality, quality, availability and rate at which its nutrients are absorbed by (i.e.: of value to) our bodies and brains. In fact, there are so many phytonutrients that are unknown or continually being discovered, now that the scientific community is focused on it, that no one can agree on just how many there are out there; Google it, and you'll find quotes from 4,000 to 100,000 and beyond.
So what are they? They are a meta-category of chemical compounds that plants have evolved to protect themselves from everything from insects to germs, fungi and UV radiation. We also know that plants have roughly 64 times as many phytonutrients as the animals we eat, according to nutritionfacts.org. Studies, like the 12-year study completed in 2013 by the Universidad de Barcelona and published in the Journal of Nutrition, showed that diets high in polyphenols - the largest category of phytonutrients - led to a 30% reduction in mortality in older adults. According to the American Journal of Clinical Nutrition, those polyphenols - which were largely unknown before 1995 - strongly support the prevention of degenerative diseases, like cardiovascular disease and cancer. AJCN goes on to say that the antioxidant capacity of polyphenols dwarfs that of conventional antioxidants like Vitamin C and Vitamin E - by ten times and one hundred times, respectively. Moreover, antioxidants catalyze the conversion/production of the vitamins into forms our bodies can use, like beta-carotene in carrots into vitamin A (more on that later).
Confused by terms like polyphenols, phytonutrients and antioxidants? We haven't yet mentioned enzymes, phytosterols, carotenoids and glucosinolates. And those are just categories. There are sub-categories, like organosulfurs, flavonoids, curcuminoids, lignans, xanthophylls and tannins (you've heard of that one - red wine!), to name just six. And then there are the chemicals themselves, which are too numerous to list.
Before you stop reading, we've gone ahead and created a graph in an attempt to demystify - both for you and for ourselves - the world of phytonutrients. This list is in no way exhaustive; it's simply meant to help you understand how the 'tree' of nutrients relates to the whole, what the categories are, what each one does - health-wise, and which (common) foods contain them.
Copyright FFFL
You can also direct download a larger copy of the chart here.
In it, we've focused on the antioxidant category - at center image in dark blue, and expanded it below, in green, purple and orange. Antioxidants are both the largest and most important phytochemical class with regard to physical health. The other four categories (flanking the antioxidants), while extremely important, are relatively simple to explain, in brief:
Enzymes serve to break down foods into nutrients, thereby improving our absorption of them. Nutritional scientists refer to enzymes as pre-digestive, because they begin to dissolve foods before the saliva in our mouths - produced by chewing - begins its own process as foods pass through on their way to our digestive tracts. As mentioned earlier, pasteurization deactivates all enzymes. This begins at 120F and is absolute at 160F - the legally required temperature by the Food and Drug Administration. Pasteurization - regulated since the 1950's, is why 65% of the population is suddenly lactose intolerant, according to Dr. Mercola, because the heating process kills the enzyme lactase in milk (and every other enzyme), whose job is to aid in the digestion of the nutrient lactose. Studies have shown lactose-intolerant people who consume raw milk products - as we reported in the second half of Week 4's post - can tolerate them without adverse effect.) A good article on why enzymes are important can be found here. It's also worth mentioning here that pasteurization has additional negative impact on the nutrient most people drink milk for in the first place: its calcium. Pasteurization renders insoluble the vast majority of the calcium milk contains. Meaning, the calcium in pasteurized milk passes through you, unabsorbed. This is a good example of what we mean when we talk about the interaction between nutrients, and the need for understanding foods holistically before we begin selectively re-engineering them.
Natural Acids are what gives foods their distinctive (and often strong) flavor, like the citric acid in lemons. Many are termed 'wholesome', and while they offer no direct health benefit, they are harmless; others are considered 'unwholesome', like the oxalic acid in dark, leafy greens. Overwhelmingly, the body can handle and dispose of them harmlessly. Occasionally, people do have sensitivity, such as those with kidney or gallbladder problems, in which case foods with 'unwholesome' acids should be limited. More info on Natural Acids can be found here.
Phytosterols inhibit the absorption of cholesterol. Thus people with diets high in phytosterols experienced lowered LDL (aka 'bad' cholesterol) levels, thereby reducing their risk of cardiovascular disease. A great overview on phytosterols can be read here. Phytosterols are predominantly found in wheat germ and vegetable oils.
Non-digestible Carbohydrates is a fancy term for what we call fiber. They are the 'insoluble' fibers of vegetables and fruit that give them shape - their structure, simply put. When ingested, these non-nutritive fibers pass through the body unabsorbed, while the vitamins, minerals, fats, proteins and phytonutrients they carry are absorbed. The major benefit of 'getting fiber in your diet' - by which we mean these non-digestive carbohydrates - is that they improve digestion and 'regularity' - and provide the added benefit of whisking along ingested toxins, thereby minimizing their contact with, and absorption by, the body. In addition, these 'prebiotic' foods play a role in gut health, lower body weight and lower cardiovascular disease. More on NDCs here.
Which brings us to the main category of this post - the buzziest of buzz words today: antioxidants. We reviewed these in brief in our last post, insofar as dark, leafy greens are one of the greatest sources for these - and many other - nutrients. As we mentioned then, the blogger Sophia Breene said beautifully in this article that antioxidants are not so much a substance as a behavior. As the name suggests, they reduce oxidation - called oxidative stress - of the various molecules inside your body. This is important because rampant oxidative stress creates 'free radicals' - those unstable cells that cause damage to you on a cellular level: your DNA, your proteins and your lipids. [We explained the molecular basis of free radical creation in our last post here.] As we said then, these free radicals are thought to be major contributors to a raft of modern disease, including cancer, Alzheimer's, heart disease, stroke, Parkinson's, fibromyalgia, diabetes, aging, cognitive decline, macular degeneration and ALS. Because of this, antioxidant phytochemicals - the largest and most important group, and one that only over the past 20 years has begun to be studied by scientists in earnest - are getting a lot of attention. So let's examine them.
As we mentioned, our graphic is incomplete. There are many major groups of phytochemicals, a (reasonably) full listing of which can be found here. We have chosen to include 3 of those in our chart, because they comprise the area of greatest study, and therefore nutritional value to you, through the food choices you make, insofar as looking to benefit from what the international nutritional science community has discovered. These include Glucosinolates, Polyphenols, and Carotenoids. Chemicals in all three categories provide significant antioxidant benefits. We will look here at what makes each group unique.
Glucosinolates: these sulfur-based compounds occur in two groups: organosulfurs and indoles. The former is found mostly in the alluvium family (onions, garlic, leeks, chives...) while the latter is found in brassicae (aka cruciferous vegetables) like broccoli, Brussels sprouts, kale, arugula, bok choy, cauliflower and others. All of these vegetables... well... stink. That's the glucosinolates. What they do is directly inhibit cancer cell growth, as well as directly kill cancer cells, by forcing their apoptosis. You see, all cells are programmed to die (apoptosis); cancer cells are great at avoiding that (i.e.: staying alive). Glucosinolates suppress carcinogenesis (the creation of cancer cells) 'in vivo' - meaning in live subjects - and have been shown to induce apoptosis (normal cell death) in cancer cells 'in vitro' - meaning in laboratories. I've include just one study - from 2003 by the NCBI - here. The research paper goes on to conclude that 'Brassica vegetables can exert a profound effect on the balance of colorectal cell proliferation and death in an animal model of colorectal neoplasia [aka uncontrolled growth of tumors or lesions]'. A diet, therefore, that includes daily intake of glucosinates like those listed above, has been shown in study after study to have an anti-carcinogenic effect on your body, to say nothing of the density of vitamins, minerals and other antioxidants they contain.
Carotenoids: these are what gives fruits and vegetables their orange, red or yellow color, as in papaya, carrots and mangoes, which are high in alpha-carotene; or, in the case of some vegetables, the green in chlorophyll may visually mask underlying carotenoids, such as in kale, spinach and chard, which are high in beta-carotene. There are two types of carotenoids: carotenes, like the alpha- and beta- ones mentioned; and xanthophylls, which are found predominantly in marine life, like shrimp, lobster, crabs and salmon, but are also present in red/yellow/orange vegetables and fruits. Xanthophlls include lutein, zeaxanthin, both of which are found in high quantity in the eye's macula. All carotenoids contribute to skin and eye health, while beta-carotene in particular has been associated with lower risk of macular degeneration, glaucoma, formation of cataracts, macular edema and other eye diseases. As far as xanthophylls go, this article by Dr. Mercola focuses on astaxanthin, which gives salmon its pink color. Dr. Mercola calls this 'the most powerful antioxidant' when it comes to free radical scavenging, 65 times more powerful than vitamin C, 54 times more than beta-carotene, and 14 times more than vitamin E. He especially advises older people to consume salmon (to which I'll add the qualifiers wild and Alaskan, for their low mercury and high omega-3 fatty acids...) because the elderly are at greatly increased risk of eye diseases.
Polyphenols: I've saved this category for last, because it's the largest, with over 8,000 compounds, and the most complex. its six sub-classes - flavonoids (the largest, by far), lignans, isoflavones, curcuminoids, stillbenoids and tannins - all exhibit antioxidant qualities, but what each group does for human health is quite distinct. Our chart begins to break down the key benefits and foods each group confers. But perhaps THE key benefit is that high-polyphenolic foods are strongly anti-inflammatory as well as being anti-oxidative. As we've discussed in several posts, chronic inflammation is an environment of ill-health in which the body is in a constant state of aroused defense, using up nutrients and immune functions in an attempt to restore balance. Stress and lack of exercise are part of the cause; but diet is a major contributor, as well. Chronic inflammation has been directly linked to many cancers, Alzheimer's and heart disease. it is also considered largely a modern, diet-induced condition, because processed foods comprise 67% of our dietary calories, according to AJCN, and 90% of our food dollars, according to Eric Schlosser. Polyphenols - and more than any other group, the flavonoids - promote an anti-inflammatory response when ingested in sufficient quantity and variety, by 'blocking the messaging molecules that promote inflammation'. On the flip side, a reduction in the intake of inflammatory foods - processed anything, pasteurized dairy and red meat - aids the body in returning to a state of repose, i.e.: non-inflammation. Thus you should both increase your consumption of anti-inflammatory foods and decrease your consumption of inflammatory foods.
So what foods are high in polyphenols? It would be as knee-jerk as it is somewhat accurate to say 'all plant foods', since the production of poly-phenolic compounds is a byproduct of plants' efforts to protect themselves from both the ultraviolet component of the sun that feeds them and the predators that try to consume them. Thus a comprehensive discussion about foods and polyphenols is nearly impossible, and totally impractical. What we can do is focus on foods we typically consume, or can/should consume, and the polyphenols that make them valuable.
Flavonoids - the biggest polyphenol category, with over 6,000 compounds - are found in a giant cross-section of foods that by any other measurement have little to do with one another, from dark blue and purple foods, like beets, blueberries, purple carrots/corn, red berries, to white foods like bananas, celery, onions and quinoa; to green foods like parsley, turnip greens, lettuces and cabbage; and the list goes on.
Tea
The single largest source of flavonoid intake among Americans is via brewed black tea, according to both World's Healthiest Foods and the USDA's own research. If you do the math based on the USDA's numbers, (predominantly black) tea comprises 75% of all flavonoid intake among Americans. Tea's key flavonoids are called catechins, which are by far of greatest nutritional value in (high-quality) Japanese matcha. Matcha sellers will tell you that their product has shown to have 137x the EGCG (epigallocatechin) content (EGCG is considered the key health-promoting flavonoid in tea) as that of regular green tea. That comparison came from the University of Colorado, comparing matcha to Starbucks' Tazo™ tea; The reality is that matcha has approximately three times the EGCG content of regular green tea. Black tea, and every other source of catechins, drops off precipitously from there. According to UC Davis' research, 'regular' green tea has on average 5x the EGCG content of black tea, 4x the epicatechin content, and 2x the catechin content - all 3 flavonoids that create its value. So drink green tea in place of black tea, and seek out high-quality matcha if you can afford it; quality matcha is expensive, though it carries many other health benefits, as we reviewed at the very bottom of last week's post. A word of caution: like anything, the quality of matcha varies greatly. That shot in your Starbucks latte may come from a cheap producer in China, and as such the health boost you seek from it may not bear out. This web link provides some good rules of thumb when choosing matcha.
Spices
But when it comes to antioxidant and poly-phenolic food, tea in general ranks far lower than many other foods, and as such should only be thought of as part of a healthy diet. The European Journal of Clinical Nutrition (EJCN) lists here the 100 foods highest in polyphenols. Tea of any kind hovers around the #50 mark. The same chart also lists, by number, the foods highest in antioxidant activity. Interestingly, dried spices - led by the #1 antioxidant and #1 poly-phenolic food - cloves - are major contributors to both. In fact, cloves, peppermint, star anise, oregano, celery seed, sage, rosemary, spearmint and thyme all make the top 15 polyphenols on their list, in order. We, as do many health experts, encourage the use of spices in your meal preparation, from oregano in your pasta sauce to cinnamon on your morning blueberries, to curries in your cooked vegetable dishes. Last week we shared a quirky video by Dr. Michael Greger - a bit of a media star insofar as antioxidant health. We'll include it again here, because he shows how easy it is to up your antioxidant content with things you already eat. As the world's greatest antioxidant, cloves can be added to soups, teas, ciders or desserts; while the world's greatest anti-inflammatory, turmeric, can easily be incorporated into a variety of cooked meals. We often think of dried foods as being less 'live' or 'fresh', and therefore of lesser value. But teas and spices - essentially desiccated and often pulverized plants - often offer concentrated forms of these key nutrients. In fact, table 5 on the USDA's flavonoid intake chart here shows that dried parsley contains sixty times the density of flavones over raw parsley. So spice it up!
Berries
That's not to ignore fresh produce. Five berries - chokeberries, elderberries, 2 types of blueberry and black currants - all make EJCN's 'top 20' polyphenolic foods list. Unlike the catechins in brewed tea, flavonoids are especially delicate with regard to heat, and thus should be consumed raw, according to WHFoods. Blueberries are the largest source of anthocyanins (the blue- and purple-granting flavonoid in berries, purple carrots and purple corn, to name three) consumed by the American public. Blueberries are of particular interest not just because people already consume them, or because they're readily available everywhere, but because beyond the anthocyanins, blueberries contain fifteen distinct antioxidant phytonutrients, making them a 'whole body' antioxidant. WHFoods goes into detail here about blueberries benefit to your cardiovascular system, cognition, blood sugar, eyes, and of course, cancer. NCBI conducted a study testing the effect freezing berries (raspberries, in this case) has on their antioxidant phytochemicals. This is important, because frozen berries, which are cheaper and widely available in supermarket freezers, are often picked at peak harvest, then flash frozen, while fresh berries are often picked pre-peak, to improve their resistance to being pulverized in the long journey from field to supermarket. NCBI found that freezing had no effect on the overall antioxidant capacity of fruits. Buying frozen fruit has the added benefit of longevity. Fresh berries must be consumed within days of purchase before becoming mealy; whereas frozen fruit is easy enough to throw into smoothies - something I do daily. In either form, berries are a great form of antioxidant, along with other vitamins, a few minerals, and dietary fiber. Trailing the 'super-berries' but also making the top 50 on EJCN's list were plums, cherries, blackberries, strawberries, raspberries (the lowest fruit in sugar), prunes, black grapes and apples - in that order.
Other polyphenols worth mention? The sub-classes lignans and isoflavones both affect our hormonal health systems. Lignans, which are nearly unique to flaxseeds, help regulate hormone levels, having been shown to help menopausal symptoms in women. For men, they have been shown to lower DHT levels, improving prostate health.
Isoflavones, soy, phytoestrogen and endochrine disruption
This is a MAJOR area of concern. The polyphenol category of isoflavones is most readily found, and concentrated, in soybeans, which have been touted by pseudo-studies to hinder cancer cell growth by mimicking estrogen, reputedly lowering risk of breast cancer in women and again improving prostate health for men. This is due to the very real fact that they are phytoestrogens - i.e. plant-based estrogens, which also makes them endochrine disruptors. Endochrine disruptors are chemicals that, at certain doses, interfere with the hormone (endochrine) systems of animals and humans. This is of great concern because of the ever-increasing production of soy products in the US.
Soy production is second only to corn in the United States, comprising 8% of all US farmland - or 3 billion bushels - which is 35% of all worldwide production. Soy is consumed in many forms: infant formula; dairy alternatives like soy milk, soy spreads and soy creamers; tofu; soy protein isolate (in 'health' and 'workout' drinks, energy bars and cereals); and fresh, in soybean form (edamame). There is so much soy being farmed, that - like corn - the industrial agro-giants are scrambling to 'add value' to foods by including cheap, plentiful soy. Today, 31% of Americans consume soy products once or more per week - which is a 50% increase over just five years ago. For all the documented benefits of plant protein over that from animals, which bears out in the research, increasing research into the area seems to point out a wide disparity on the purportedly beneficial link between soy intake to breast cancer. The benefit seems to differ widely according to race, with largely no benefit among studies of Caucasians, and much more consistent benefits reported in studies of Asians, who have been consuming soy for 5,000 years. NCBI goes into depth on global studies here, under bullet point 5. Worse still, as an endochrine disruptor, scientists frankly have no idea - and wildly conflicting research results - as to what the increased consumption of soy will do to our hormone (endochrine) systems. Over 35% of bottle-fed newborns receive some of their protein from soy, according to a cautionary Men's Health article here. In doses we have yet to identify, soy consumption has the ability to disrupt our hormonal balance. Just look to retired US Army Intelligence officer James Price, who upon drinking a whopping 3 quarts of soy milk a day, developed breasts, experienced major hair loss, reduced sexual desire (and abilities) and mood swings. And while James' intake is admittedly far higher than normal, he eats other foods, whereas newborns - whose futures have yet to be studied, given the relative novelty of soy today - consume 100% of their nutrients via formula. Scientists are concerned that they don't know what long-term effects on hormonal (reproductive) systems soy-rearing will have on them. At the root of the issue is the fact that we don't know the acceptable level of phytoestrogen in our diets that will not trigger endochrine havoc. What we do know is that the FDA is to 'thank' for the uptick in soy consmption, which increased dramatically when they approved a health claim linking soy consumption to a reduction in heart disease. You can see the data here.
In the end, as with everything, it is a matter of threshold. We are not telling you to avoid soy. It's somewhat impractical anyhow, given its market saturation. We are cautioning against jumping on the band wagon of the latest trend, where soy is thought of as a simple switch from cow's milk. We question the value of both, and caution you to consume either in small amounts, for reasons we've explored in depth with respect to dairy, and now discussed here insofar as soy is concerned.
So what to take away from all this?
Phytonutrients abound in the plant kingdom - 64 times as common as in the animal kingdom. Phytonutrients are an invaluable source of antioxidants, which keep your cells, DNA, lipids and proteins healthy and on track. They kill cancer cells, and prevent the formation of new ones. They confer all manner of health benefits, from skin health to eye health to cardiovascular support to nutrient absorption (bio-availability) to the people who consume them. And the sheer number of phytonutrients - likely over 100,000, with more being discovered every day - makes it important to consume a broad variety of fruits and vegetables in order to capture as wide a cross-section of benefit as is practical. 'Eat your colors', as the adage goes. Phytonutrients are the reason that statement (intuitively) exists, because they are the chemicals that create the color in our foods. Humans are complex systems that science is just beginning to understand. We evolved from and with Nature, because of it, and if Nature couldn't provide us with adequate nutrition to flourish for the millennia we have roamed the Earth before taking agricultural root just 10,000 years ago, we would simply not exist.
I created this website because we no longer produce our own foods, and now rely on companies with shareholders, profit-centered motivation, sophisticated marketing budgets and back-pocket politicians who create legal policy around issues of food production and consumption. In this context, most of us really don't understand food anymore, or exert much control over our intake of it, in the face of the ubiquity of unhealthy choices. It is therefore extremely important that we understand the nutritional profile of whole, plant-based foods as best as we can - foods that feed from the same root nutrients that we do, against the context of manufactured, industrial food-like products that isolate components of foods, alter and recombine them radically, and tell us they are as healthy as - or healthier than - the things that Nature grows. If there's a take-away from this week's post, it is that Nature - of which we are a constituent part - is holistic, while science and commerce are decidedly compartmentalized. And we are gambling with our own - and our families' - health.
So drink green tea - matcha if you can afford it; eat your colors - the whole rainbow of fruits and vegetables; include spices in your food preparation - they're cheap, long-lasting and phytonutrient-dense; base your diet on plant-based foods (that said, eat wild Alaskan salmon at least once weekly); avoid packaged foods that take a Frankensteinian approach to nutrition; avoid over-relying on any one category of food, since doing so can throw your system's balance off - like that of soy; and follow the sun, like the plants - not the balance sheet, like the industry.
