Fructose: Friend or Foe?

Illustration © D. Yael Bernhard

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My client gazed into the distance with a faint smile as he mused about his past, remembering with nostalgia how his grandmother had fed him as a child. “Every day she gave me a ham sandwich and orange juice for lunch,” he said, adding quickly, “I’m not about to give that up.” 

Once again I was struck by the power of childhood associations. This man was willing to cut back on sweets, except for those that held a special fondness in his heart. It was as if orange juice couldn’t be bad – nor, in his mind, could its high glycemic load affect his incipient diabetes. After all, he had been drinking it all his life. 

Food can be an expression of love, and for a young boy raised by his grandmother, a form of emotional sustenance every bit as nourishing as macro and micronutrients. But though we may love certain foods and the people who feed them to us, do these foods love us back?

When my children were little, I packed water bottles in their lunch boxes. Twenty years ago, savvy parents already knew fruit juice was a significant cause of childhood obesity. It made sense: the apple juice squeezed into a half-pint bottle came from more apples than a child could possibly eat. The fruit sugar was too concentrated, and too high in calories.  

Little did I know that calories hardly figure into the weight gain fruit juice causes, or that fruit sugar itself, apart from being fattening, can be harmful to human health. Growing up in the 1960s and 70s, I was regaled with the virtues of orange juice, considered a superior source of vitamin C. That glass of liquid sunshine lit up the breakfast table for children all over America, and is still hailed today as a wholesome beverage. Since fruit is an important part of a healthy diet, that means fructose – the sugar that occurs naturally in fruit and honey – must also be healthy – right? 

So I figured, as a young mother who unwittingly plucked fruit juice sweetened cookies and jams from the supermarket shelves and dropped them in my cart. No white sugar for my kids, I thought triumphantly! Surely the dehydrated juice of a grape or a pineapple must be better.

My former self would have been shocked to learn that against all familiar logic, sucrose – common table sugar, a disaccharide composed of half fructose and half glucose – is actually safer than pure fructose alone. How can that be?  

The purpose of fruit is to feed the new life in a seed until it can grow roots, sprout leaves, and photosynthesize for itself. To accomplish this, fructose forms as part of a complex matrix of plant sugars, fiber, phytochemicals, minerals, and water. Nature’s plan does not include prying these components apart, any more than our eyes are meant to see from outside our heads. Fiber is essential, not just to maintain the structural integrity of the plant, but for the animals that eat it (and help spread the seeds of the fruit). Fiber slows the rate of digestion, and feeds our beneficial gut bacteria. Separating fructose from fiber by mechanical means involves breaking chemical bonds, and changes the message it delivers to our bodies. Unbound by its natural fiber, “free” fructose cannot be burned directly as energy, and puts a heavy burden on the liver to process it. This triggers insulin resistance within the liver, and the formation of free radicals, which in turn cause oxidative stress and chronic inflammation.¹ Fruit juice causes weight gain not by accruing calories, but by signaling the body to store fat. Think of a bear gorging on berries before winter. As fruit ripens in late summer and early autumn, fructose signals the body to prepare for a season of scarcity by conserving energy as fat. Fructose is the molecule of energy storage, while sucrose is the molecule of energy utilization. 

The negative effects of fructose go beyond inflammation and weight gain. In response to free fructose, the body produces uric acid, a breakdown product of both fructose and alcohol. Uric acid is often associated with gout, but it also contributes to cancer, kidney disease, dementia, and heart disease.² Uric acid inhibits our cellular energy factories known as mitochondria, and compromises the beneficial effects of nitric acid, which relaxes blood vessels, lowers blood pressure, and increases insulin sensitivity. Once thought to be a canary in the coal mine that signaled the onset of metabolic syndrome, uric acid is now known to be a major cause.

Since fructose cannot be burned directly as energy, the liver stores it as fat – contributing to non-alcoholic fatty liver disease (NAFLD), a silent epidemic which afflicts 24% of Americans today.³ NAFLD has become increasingly common, in recent years even among children. Unfortunately, membership in this growing club is not announced on TV commercials or displayed on fruit juice containers.

Fructose also accelerates the process of glycation, the fusing of proteins and sugar which partly disables the functioning of protein molecules. Glycation is what makes skin wrinkle with age, and what determines the A1C blood sugar test, as blood glucose adheres to the proteins of hemoglobin. Compared to other simple sugars, fructose increases glycation by a factor of ten, wreaking havoc on human health.⁴ While some glycation is inevitable, it's best to eat high-glycemic fruits such as bananas, mangos, grapes, and all dried fruit in moderation.

In order to be absorbed, fructose must first be phosphorylated, which consumes extra energy in the gut, stressing the tight junctions that line the intestines and causing leaky gut. Fructose inhibits the sensitivity of leptin, the hormone that suppresses hunger, leading to increased appetite. And in opening the pathway to creating fat, free fructose stimulates lipogenesis, contributing to the build-up of cholesterol in the cardiovascular system.⁵

As these facts ripened in my mind, my perception of the sparkling spritzers and fruit juice sweetened treats in my kitchen began to change. What once seemed friendly and convenient, now looked fake and frightening. I replaced fruit juice with herb teas and nourishing herbal infusions. For a fruity flavor, my favorite tea blends are green tea with elderberries and rose hips with fenugreek seeds. To save money, I pick elderberries and wild rose hips near my home, buy the other herbs in bulk, and combine them myself. For extra zest I add a squeeze of fresh lemon, or dry organic orange peels on my wood stove. Homemade kombucha fermented with berries is another delicious option. Store-bought kombucha may have added sugar or fruit juice.

The most dangerous fructose of all is high fructose corn syrup (HFCS), which is up to 75% free fructose – a far higher concentration than would ever occur naturally. HFCS is made by chemically converting corn starch by use of an acid-enzyme called chloralkali. Chloralkali contains mercury, while the corn itself contains glyphosate, the toxic weedkiller also known as Roundup. I think of glyphosate as the DDT of the 21st century, destructive to humans and the environment alike, with untold stories of sickness and disease unfolding by the hundreds of thousands each year. Functional medicine physician Dr. Mark Hyman calls HFCS “one of the most dangerous compounds known to humankind.”⁶ Yet this insidious ingredient is subsidized by our government, and hides in many processed foods, condiments, and beverages. Buyer beware! Read labels, and if you find HFCS, put it back on the shelf. Ask for ingredient lists in restaurants. I recently discovered this evil sweetener in a butternut squash soup in my favorite local café. The owner has not yet answered my email – but I hope she reads it and takes to heart the destructive power of this chemical that is heavily associated with cancer and other serious health problems.⁷ It’s time to forge a new normal: the food industry needs to become more aware of health, and the health industry needs to become more aware of food.

If fructose is so bad, why eat fruit at all? In the world of nutrition, context is everything. When it comes to good health, the lowest hanging fruit is in its whole, natural form. Unlike free fructose, whole fruit is broken down slowly in the digestive system and absorbed gradually into the bloodstream. The slower the rate of digestion, the more nutrients are absorbed, and the less insulin is released. Fruit is a whole package – juicy, flavorful food you can love that loves you back. In its whole, natural form, fruit is rich in both fiber and phytonutrients: beta carotene in cantaloupe, flavonols in cherries, polyphenols in black currants, anthocyanins in blueberries, catechins and ellagic acid in strawberries and pomegranates, quercetin in apples, hesperidin in citrus fruits, resverotrol in grapes, and lycopene in tomatoes and watermelon. Even the white pith that surrounds the sections of an orange is rich in bioflavonoids. The human body has no biochemical requirement for fructose, but it does need these invaluable antioxidants and beneficial compounds in order to be healthy.⁸ 

I didn’t have the heart to tell my client that by giving him orange juice every day, his grandmother was watering the seeds of his present-day health problems. She might as well have given him sugar water, as even the nutrients normally found in citrus are destroyed by processing and pasteurization (and then added back in artificial forms that are poorly absorbed, such as ascorbic acid). She didn’t know any better, but half a century later, we do. Commercial fruit juice is fractured food, and fructose, when separated from its natural substrate, is an isolated, concentrated sweetener, bearing little resemblance to its fresh and fragrant, pulpy and fleshy origins.   

Food isn’t just calories – it’s information. It’s cellular code. It’s a message from the earth to your body. It’s sunshine captured in colors and textures, transmitted through a symphony of biochemical compounds. One soloist can’t make the music of a whole orchestra. So skip the orange juice, and eat the orange. Take the money you save on juice and buy yourself a beautiful water bottle. Your liver will thank you!

Eating whole fruit does not cause problems; in fact, studies have shown it may even decrease the chance of developing diabetes.⁹ Pick your fruit directly from the tree, and you’re eating a live food. Farmers’ markets are second best. Fruit is your friend, as long as it’s intact. Berries are among your best friends, as they’re high in anti-oxidants, with a low glycemic load.  Unless you can harvest your own, frozen berries are superior, as they’re picked when ripe, and less expensive than fresh berries. Wild berries are best of all, as these plants grow from soil rich in micronutrients, and produce more phytochemicals for their own benefit and protection. Of all the store-bought berries, goji berries are the highest in antioxidants and are also prized for their adaptogenic properties. Cranberries, elderberries, and blackberries are also high in antioxidants.

If you do consume free fructose in the form of fruit juice, jelly, jam, syrup, wine or brandy, try to put fiber and healthy fat in your belly first. Full-fat yogurt, nuts, whole seeds, nut butters, and whole grains (not whole grain flour) are a few examples. These foods slow down digestion. A fruit smoothie is better than juice, but even this will partly destroy the precious fiber in fruit. Ideally, stick to fruits with a glycemic load of 11 or lower (not to be confused with glycemic index, which only compares one fruit to others), such as berries, apples, pears, oranges, and apricots.¹⁰ Fatty fruits such as olives, coconut, and avocado are ideal. Their healthy oils and abundant fiber create a feeling of satiation, reducing appetite and speeding up metabolism.  

Fruit is what we make of it: an ally for underlying health, or an enemy that undermines longevity. Sometimes I miss the smooth, sweet taste of liquid fruit, but when I weigh the loss against the benefits, it’s clear there are much greater pleasures in life. No wonder the mythical tree of life in the Garden of Eden was a fruit tree. The Bible tells of the two-sided nature of knowledge, bringing both the blessing of consciousness and the curse of corruption. The same is true of the fruit itself. Once we’re aware, we can choose.

To your good health –

Yael Bernhard
Certified Integrative Health & Nutrition Coach

Yael Bernhard is a writer, illustrator, book designer and fine art painter with a lifelong passion for nutrition and herbal medicine.  She was certified by Duke University as an Integrative Health Coach in 2021 and by Cornell University in Nutrition & Healthy Living in 2022.  For information about private health coaching or nutrition programs for schools, please respond directly to this newsletter, or email dyaelbernhard@protonmail.com. Her art newsletter, “Image of the Week,” may be found here. Visit her online gallery of illustration, fine art, and children’s books here.

Information in this newsletter is provided for educational – and inspirational – purposes only.

1. https://www.levelshealth.com/blog/why-fructose-is-bad-for-metabolic-health

2. https://www.sciencedirect.com/topics/medicine-and-dentistry/fructose-metabolism

3. https://www.niddk.nih.gov/health-information/liver-disease/nafld-nash/definition-facts

4. https://en.wikipedia.org/wiki/Glycation

5. Dr. Mark Hyman, What the Heck Should I Eat?, Little, Brown & Company 2018, pg129

6. The Doctor’s Farmacy podcast-ep624/https://drhyman.com/blog/2022/11/02/podcast-ep624/

7. https://usrtk.org/pesticides/glyphosate-health-concerns/
https://www.levininjuryfirm.com/when-will-the-roundup-lawsuit-settle/

8. https://www.nal.usda.gov/human-nutrition-and-food-safety/food-composition/phytonutrients

9. https://pubmed.ncbi.nlm.nih.gov/25074631/

10. Dr. Mark Hyman, What the Heck Should I Eat?, Little, Brown & Company 2018, pg135