As fresh juicing and smoothies becomes more popular, it’s important to know that there are a few minor risks. I stress that these are VERY minor, and nothing that should discourage anyone from juicing or smoothies with all the amazing benefits including better health, more energy, a delicious alternative to sugary drinks especially for your children, and my favorite, the most convenient way to consume all the recommended daily servings of fresh fruits and vegetables. In fact, a fresh juice or smoothie is just about the healthiest thing you can do for yourself, your family, and your friends! So let’s be aware of these concerns, but keep a healthy perspective!
Food Borne Illness
The CDC reports that produce is the leading cause of food poisoning in the US (although more hospitalizations are due to dairy products and more deaths are attributed to poultry). Produce with the greatest risk are melons (the rough skin traps bacteria and gets carried to the flesh when cut) and packaged pre-cut leafy greens.
The CDC and FDA recommend rinsing your produce in cold water, don’t buy pre-cut veggies and fruits, and grow your own sprouts. Washing with soap is not recommended. For easy guidelines see this article by the University of Maine.
Add a little vinegar for additional protection. A study published in the “Journal of Food Protection” found that washing apples with vinegar and water reduced bacteria significantly better than water alone. The premier food magazine, “Cook's Illustrated,” sponsored a similar experiment and found that vinegar killed approximately 98% of bacteria on the surface of fresh fruits and vegetables. No soaking required! And no vinegar taste! Just spray white vinegar on your produce and rinse.
But let’s put this in perspective I know folks who rarely rinse their produce and have never had a problem. I’m one of them! However, if you’re pregnant, or you're making juices or smoothies for your children – both have a greater risk of infection and illness - I’d surely rinse all produce. And every time I read something about the working conditions of huge farms that grow and harvest commercial foods, I start rinsing all my produce! Unlike packaged beverages which undergo pasteurization to eradicate harmful organisms, fresh juice can only be made less risky by rinsing your produce. Also, storing fresh juice makes it more vulnerable to bacteria so it’s best to drink it right away.
Some seeds, rind, and leaves of common fruits and vegetables should not be eaten! This will likely surprise you as much as it did me! The seeds of apples, peaches, apricots, cherries, and raspberries, as well as the leaves of carrots, rhubarb, parsnip, and Queen Anne’s Lace (wild carrot) contain toxic compounds, but the amounts are so minute as to be of no real concern.
The major compound is known as amygdalin which produces cyanide, but the amount is so small that your body easily neutralizes it. There are claims that amygdalin has positive uses including cancer treatment. The American Cancer Society reviews this claim in a thorough and balanced article, and for an alternative view click here. The bottom line is that you would have to eat handfuls of these seeds or pits AND DIGEST THEM to experience serious illness. The seeds and pits have a tough coating impervious to digestion by most mammals. Symptoms of amygdalin toxicity are severe stomach cramps, headache, dizziness, and seizures. However, if too many seeds were eaten and digested, one would likely vomit a few times and not develop any other symptoms.
The rind of orange and grapefruit has a small amount of a toxic compound now used as an insecticide. Ingesting a small amount is absolutely safe for you and your pets, but several orange peels will definitely upset the stomach.
There is also mention of toxic substances in some sprouts. This is another one of those pieces of info that's interesting but of no real health concern. In the interest of awareness here's a brief review of toxins in sprouts. Lathyrogen is found in an inedible species of bean in the genus Lathyrus. Inedible so not a concern. Saponins are found in bean sprouts and are not harmful, though some claim this is so because outside of the body in test tube conditions saponins kill red blood cells. They are not only harmless in the body but extremely beneficial for lowering cholesterol, protecting against heart disease, and fighting certain cancers. Canavanine is a toxic compound found in alfalfa seeds. However, as with the toxin in apple seeds, it is so minute as not to be an issue. An adult would have to consume 14,000 milligrams of canavanine at one time to feel any toxic effects. A large helping of alfalfa sprouts gives you a few milligrams. For more about these compounds in sprouts go to this link.
A while we’re on the subject of stomach upset, certain fruits and veggies are so powerful that you may experience some stomach distress if you drink too much of them. Too many leafy greens or wheatgrass can do this. For others, too much beet will do the same.
For those with sensitive digestion, mixing raw fruits and veggies can do this. I mix them every day with no ill effect. Standard nutritional rules state that in generally fruits and veggies should be eaten separately, though certain fruits go well with certain vegetables. In fact certain mixes are highly recommended for juice fasting and dieting, and for fighting diseases. The most common ‘ill effect’ of mixing fruits and veggies is gas, because fruit digests faster and uses different digestive enzymes. Carrots and apples are considered exceptions – carrots go well with any fruit and apples go well with any veggie.
This is a concern only for those who limit themselves to juice or smoothies alone for long periods, especially if you’re pregnant, a young person still growing, and women in and past menopause. You can get all necessary nutrients from fruits and vegetables, but special attention needs to be paid to nutritional requirements during long juice fasts and diets. The nutrients which need special attention are iron, protein, calcium, B12, zinc, and Omega 3 fatty acids. These are critical nutrients that are difficult but not impossible to get from a vegetarian, vegan, or all-juice diet.
Medical and Dental Issues
Grapefruit juice is contraindicated if you take certain medications. Talk to your physician or pharmacist if this is a concern.
If you have any thyroid issues, compounds in raw cruciferous vegetables can interfere with your treatment. Again talk with your physician because thyroid and other health problems can be effectively improved with certain fruits and vegetables. Cruciferous veggies include kale, broccoli, cabbage, bok choy, cauliflower, turnips, arugula, Brussels sprouts, radishes, collard greens, kohlrabi, rutabaga, and watercress.
Another medical concern is diabetes. The old rule of thumb is that anyone who is diabetic should stay away from fruit and sweet veggies such as carrots, beets, etc. Recent research has overturned this with the discovery that many fruits and veggies have compounds that actually help regulate sugar levels better than cooked food. This is exciting news for diabetics so talk to your physician right away!
There is concern about the issue of fiber. Fresh juice separates 'pulp' from juice. The pulp is primarily insoluble fiber. Soluble fiber remains in the juice. Nonetheless, juice provides less fiber than the whole food unless one returns the pulp to the juice. For those who need more fiber in their diet, blended drinks (popularly known as 'smoothies') may be a better choice since they do not separate pulp from the juice. Pulp is also added calories so for weight loss, juice is a better choice.
The National Osteoporosis Foundation points out that compounds in dark leafy vegetables (kale, spinach, etc.) can interfere with calcium absorption. They recommend that these rich foods be added to your juice recipes 2-3 times a week instead of every day.
Spinach is also high in oxalate, a compound that can lead to the formation of kidney stones. People with calcium oxalate kidney stones should avoid overdoing this veggie.
Don’t juice too many tomatoes or oranges if you have acid reflux since the high acid content can aggravate and even lead to acid reflux.
Finally, there is a greater risk of gum disease and tooth decay chiefly among children and teenagers whose diets are entirely vegetables and fruits (vegan and vegetarian) without proper attention to the nutrients mentioned above according to Dr. Ludwig Leibsohn of the Academy of General Dentistry. These nutrients are not easily found in a strict fruit and veggie diet.
Plus 1 More!
I've just added this sixth concern based on new information I've learned about sugar. And it's so shocking that when I rewrite this article, this concern will take over the top spot!
We as a culture over-consume so much sugar, whether from healthy raw organic fruit or from processed foods, and the effects are far worse than we know. So I am seriously advocating as does the leading proponent of raw foods, the Hippocrates Institute, that we eat less fruit and more vegetables. For a complete look at 4 eye-opening facts that the sugar industry doesn't want you to know, see this article.
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Kilonzo-nthenge A, Chen FC, Godwin SL. Efficacy of home washing methods in controlling surface microbial contamination on fresh produce. J Food Prot. 2006;69(2):330-4. doi:10.4315/0362-028x-69.2.330
Dang T, Nguyen C, Tran PN. Physician Beware: Severe Cyanide Toxicity from Amygdalin Tablets Ingestion. Case Rep Emerg Med. 2017. doi:10.1155/2017/4289527
McMacken M, Shah S. A plant-based diet for the prevention and treatment of type 2 diabetes. J Geriatr Cardiol. 2017;14(5):342-354. doi:10.11909/j.issn.1671-5411.2017.05.009
Han H, Segal AM, Seifter JL, Dwyer JT. Nutritional Management of Kidney Stones (Nephrolithiasis). Clin Nutr Res. 2015;4(3):137-52. doi:10.7762/cnr.2015.4.3.137