Sensitivity vs Intolerance vs Allergy

Some foods we love, others we hate. Image source here. 

The difference between a food sensitivity, food intolerance, and a food allergy: 

Food Sensitivity

1) Timing: delayed reaction occurs most often

2) Symptoms:
- Diarrhea or constipation
- Bloating, gas, flatulence, cramps
- Acid reflux (GERD)
- Headaches
- Fatigue, sleepiness
- Mental disturbances
- Brain fog or hyperactivity
- Skin reactions
3) Types of sensitivities: you can be sensitive to anything! But the most common ones are gluten, wheat, dairy, nightshades, soy, and corn.
4) Immune response: IgA or IgG (meaning delayed immune reactions)
5) Tested: with blood work against 96 common foods or an Elimination Diet. Not identifiable using a skin prick test!
6) Other notes: some food sensitivities can resolve if avoided for a consistent period of time, can develop at any time and at any age

Food Intolerance

1) Timing: slow onset. Eat the food, feel fine, hours later feel yuck.
2) Symptoms:
- Diarrhea
- Bloating, gas, flatulence, cramping
- Nausea, vomiting
3) Types of intolerance: lactose intolerance against lactose (in dairy), food additives (food dyes, sulphites, additives, etc), food poisoning (intolerance to the bacteria or toxin), etc
4) Immune response: body lacks the enzyme to break down this food/substance.
5) Tested: breath test for lactose intolerance, trial-and-error (symptoms improve with the offending agent is removed or avoided)
6) Other notes: some people can take the enzyme that they are lacking in order to eat the offending food, e.g. Lactaid, but I don't recommend this, especially not long-term.

Food Allergy

1) Timing: immediate onset of symptoms. Only a tiny bit of the allergen is needed to set-off the immune system. Often a medical emergency. Sometimes carry Epi-pens.
2) Symptoms:
- Skin reactions
- Eye itchy and redness
- Chest pain and shortness of breath
- Lose consciousness, go into shock
- Swelling
3) Types of allergies: this can be anything! But common ones are peanuts, other nuts, eggs, and dairy.
4) Immune response: IgE reactions (meaning an immediate immune response to the allergen)
5) Tested: this type of allergy is often determined using the skin prick test
6) Other notes: often have food allergies for life, often diagnosed/determined in childhood

Others Food Reactions

Celiac Disease - an autoimmune disease in which the body reacts to its own enzyme that digests gluten (gliadin), causing a inflammatory, cross-reaction with the gut lining.

Diabetes - no, diabetics are not allergic to sugar! They just don't have insulin (or don't respond to insulin in type 2) to get the glucose into their cells; therefore they have to monitor their glucose/sugar levels carefully to not consume more than the level of insulin they have or can handle.