Fruits and Vegetables Aren't Good for Every Body All the Time.

It's hard to believe, but it's true.  We've all heard or read news reports about how people ought to reduce their consumption of foods high in processed sugars, starches and transfats and increase their consumption of fresh fruits and vegetables. For the majority of humans, this is true.

But for about 1/4 of the North American population, certain types of fruits and vegetables may not be fully beneficial. That doesn't mean we should binge on foods that cause demonstrable injury.  It does mean that some of us need to be very discerning about what fruits and vegetables, and how much and how often, we eat.

Why?  It gets down to genetics.  If an individual has a variant that does not allow that person to effectively metabolize a specific form of a molecule or protein, the cumulative presence of that molecule or protein (or the body's reaction to it, or the ingestion of a harmful substance that hitches a ride on our food), can damage our soft tissue, starting with the epithelial mucosa (see Meet Your Inside Skin: What is Epithelial Mucosa?), which is our first line of defense against absorbed, ingested and inhaled foreign agents, proteins and molecules.

Here's a list of ways fruits and vegetables can cause negative impacts on the human body, directly or indirectly:

A) allergens, B) toxins, C) pathogens and biotoxicity, and D) autoinflammation and autoimmunity. 

Most of these causes induce "systemic reactions," meaning that symptoms occur in multiple systems of the body. Therefore, good medical detective work is needed to discern which cause may be affecting you.

A) Allergens

1. Most people are aware that plant pollen contains proteins that can evoke an inflammatory response. 

Mild responses include nasal congestion, watery eyes, itching, rashes and hives. Moderate reactions include chest tightness, heart palpitations, wheezing, difficulty breathing, weakness, dizziness, light-headedness, flushing/facial redness, face, eye and tongue swelling, difficulty swallowing.

Further, individual fruit and vegetable proteins that are structurally similar to a plant pollen can also elicit these responses as well as induce a severe gastrointestinal kickback in the form of nausea, vomiting, diarrhea, cramping, bloating and flatulence. Allergic reaction to food proteins generally is well known, extending to more than the proteins in fruits and vegetables.

Whether ingested through food, inhaled from the air, or absorbed through the skin, allergic reactions may also include severe and immediate life-threatening changes to neurological function, including unconsciousness and anaphylactic shock, which is a sudden drop of blood pressure and closing of the airways.

2. What is less well known is the extension of allergic reaction to other soft tissues of the body. 

Oral Allergy Syndrome is the inflammation of the mucosa in the mouth, throat, and esophagus with symptoms of tingling, itching, swelling, blisters, and soreness from pollen-related food proteins.

As examples, those with an allergy to birch tree pollen may have an oral allergy response to pitted fruit; those with an allergy to ragweed pollen may have a problem with melons.

3. More challenging is that oral allergy symptoms can progress to involve additional triggers. This is termed Pollen-Food Allergy Syndrome.

When individuals have allergies to multiple types of pollens, engage in stress-inducing activities (e.g. exercise), ingest metabolic-demanding drugs (e.g. NSAIDS) or consume tissue-harming foods and beverages (e.g. alcohol), additional oral allergy syndrome responses may occur in the face, eyes, nose, sinuses and ears

4. With regard to the health of our epithelia, allergic reactions damage mucosa tissue.

Two articles of the dozens available note this fact:

G. D'Amato+ 2005 point out that airway inflammation increases airway permeability. Fontaine+ 1975 indicate that cow's milk protein allergy caused small intestinal mucosal damage and partial villous atrophy [note: villi are the finger-shaped "hairs" on the epithelium of the small intestines that capture nutrients for absorption by the body].

"Oral Allergy Syndrome" and "Pollen-Food Allergy Syndrome," The American Academy of Asthma, Allergy & Immunology,, accessed 12/8/2018.

G. D'Amato, G. Liccardi, M. D'Amato, S. Holgate, Environmental risk factors and allergic bronchial asthma. Clinical and Experimental Allergy, Volume 35, Issue 9, September 2005, Pages 1113-1124.

Fontaine J.L., Navarro J., Small intestinal biopsy in cows milk protein allergy in infancy. Archives of Disease in Childhood,1975; 50: 357-362.

 Journal for Oto-Rhino-Laryngology, Head and Neck Surgery, 2003; 65: 348–352

B) Toxins

C) Pathogens and BiotoxicityD) Autoinflammation and Autoimmunity

Helen C Harrison, M.A.

Consultant, Educator, Researcher, 951-438-5531

The FDA has not reviewed the contents of this website. This information does not claim to prevent, diagnose, treat or cure any medical condition. It is provided for educational purposes.