Vegetables: Is The Tomato Toxic?
vegetables have become bone of contention in
health circles recently; for all the talk about
lycopene and beneficial antioxidants, members of
family Solanaceae have been blamed for causing
arthritis, various other types of inflammation,
and a wide range of allergies.
Since this family of plants contributes some of
the most delicious culinary vegetables raw
foodists eat, such as tomatoes (which I love devouring in
massive quantities), ground-hugging, tangy
tomatillos, tamarillos (which first repulsed me
and then won my heart when I discovered them at a
market high up in the mountains of Bali), sweet
peppers, and some staid members like the eggplant,
it would be a shame if we needed to avoid them for
So what's the verdict?
Vegetables: What's Wrong With them?
If you were a boy scout or
attended summer camp, a smart counselor may have
warned you away from a number of berry-growing
bushes you discovered on hikes through the woods.
At least some of those plants were probably of the
Solanaceae family, and the term deadly nightshade,
often applied to them, wasn't a mistake. A number of
these wild-growing nightshade vegetables can be
highly toxic. They contain alkaloids - chemical
substances acting as natural pesticides to drive
off, incapacitate, or kill predators -, and
glycoalkaloids, which have been known to poison
people eating green, uncooked potatoes (potatoes are
also a nightshade).
The fruit and leaves of these plants still poison
and kill people in the modern era (1), (2).
millenia people have eaten nightshades specifically
to be poisoned and experience hallucinations. The
famous mandrake root is one example. The steroid
alkaloids in these plants can block certain nerve
activity, which leads to muscle twitching, temporary
paralysis, difficulty breathing, and various changes
to audio and visual perception.
A number of animal studies have found livestock
eating wild nightshades, including Solanum
malacoxylon, and Solanum sodomeum (the Solanum genus
also contains eggplant, tomatoes, and peppers), are
frequently sickened by arthritis-like inflammation
or killed (3) (4).
Nightshade Vegetables: So What About The
Not all nightshade vegetables were created equal,
and many of the harmful properties found in wild
members of of the family are absent or greatly
reduced in their cultivated counterparts. The
edibles we're interested in are members of two
genera: Capsicum and Solanum, or the pepper genus
and potato/tomato/eggplant genus, respectively.
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salad every night of the week. Don't
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Before you go uprooting your tomato and pepper
plants, keep in mind they have only a tiny fraction
of the alkaloid content of the wild-growing deadly
nightshades and that glycoalkaloids are reduced
during a fruit's ripening process.
Our ancestors weren't stupid, and would have noticed
any large-scale problems arising from the
introduction of tomatoes, peppers, and other
nightshades into their diets. Today, large swaths of
humanity eat large amounts of nightshades without
apparent negative side effects.
Yet there is a minority of people who've found the
(inaptly named) nightshade diet containing no
members of the family have brought them relief from
certain symptoms. Many claim tomatoes and arthritis
are related, for instance. It's become popular for
doctors and nutritionists to suggest those suffering
from arthritis do a trial elimination of the
Solanaceae family, along with other known
But is there any evidence these diets work for
Nightshade Vegetables: Any Evidence That
Nightshade Diets Work?
There's plenty of anecdotal
evidence indicating problems with nightshade
vegetables. Surveys have found many people suffering
from arthritis believe they find relief when
nightshades are eliminated from their diet (5), and
a trip to many health forums on the internet will
put you in contact with people who blame them for
causing all manner of diseases.
Nightshade diets haven't fared nearly as well in
peer reviewed trials, however.
The majority of dietary studies looking at the
effect of nightshades have also involved the
elimination of other foods known to cause
inflammation, such as dairy
making it hard to be sure exactly what's causing the
problem, even if the the elimination diets work..
One study that eliminated dairy, red meat, citrus,
peppers, tomatoes, alcohol, and coffee (the Dong
diet) as part of a double-blind placebo controlled
trial found there was no statistical improvement
difference between the Dong followers and the
controls. Notably, though, two patients on the dong
diet did see significant improvements, but their
gains disappeared after eating meat,
A more effective treatment for arthritis is fasting
patients and then placing them on a vegan diet, but
this still only improved 25% of the patients (7).
Overall, no one has so far shown a solid link
between the elimination of nightshades and
improvements in inflammation-based diseases.
Nightshade Vegetable Exclusion: Worth A Shot?
I think it's likely a sizable minority of people are
allergic to one or more nightshades or suffer from
sensitivity to alkaloid chemicals in general, an
idea that has some backing (8). The general alkaloid
sensitivity makes a lot of sense because while in
one survey 37–43% of patients with
inflammation-based diseases reported an increase in
disease symptoms after intake of certain
alkaloid-containing foods, there appeared to be no
differentiation among the different types of
diseases (9). This may mean the alkaloids are
causing general inflammation which manifests itself
in various ways among sensitive people.
However, a large amount
of people simply have nightshade allergies. One
study of people consuming eggplant in India, where
it's a major staple, found that nearly 10 percent of
participants reported itchy skin and/or mouths after
handling or eating eggplant (10).
Among those suffering from allergic reactions to
food, which is believed to be more than 50 million
people in the United States, between 1.5 and 16
percent have various allergic reactions brought on
by tomatoes (11).
I'm fairly certain I have a minor tomato allergy
myself. As much as I love tomatoes, I know when I
eat them I frequently break out in small-scale itchy
skin rashes and bumps. For years I wondered why I
had periodic bouts of acne on my face until I tried
eliminating them, which cleared up my skin.
Even so, their effect on me is relatively minor if I
only eat them periodically, and I had no
reservations about including them in several of the
recipes in Savory
Raw Dressings And Sauces.
I see no reason to suggest asymptomatic people avoid
nightshade vegetables. If you believe they may be
bothering you, it's easy enough to figure it out.
Simply do a 30-day
nightshade elimination diet. If you've found relief
by the end of that trial, you have your answer.
Nightshade Vegetables: Following Up
Learn how to eat
a healthy raw food diet.
Figure out how nightshade
vegetables fit into among the foods you should
embrace or avoid if you want health.
Want some amazing and healthy low-fat raw dressings
to spice up your salad? Check out Savory
Raw Dressings And Sauces.
Nightshade Vegetable Sources:
poisoning". Br Med J. 2 (6203): 1458–9. 1979-12-08.
PMC 1597169. PMID 526812.
RF, Forbes GB, Hawkins ES (1948-09-11). "A Fatal
Case of Solanine Poisoning". Br Med J. 2 (4575):
518. doi:10.1136/bmj.2.4575.518. PMC 2091497. PMID
RH. Active vitamin D-like substances in Solanum
malacoxylon and other calcinotic plants. Nutrition
Reviews 1975; 33:1-5
4) Davis GK.
Effect of a nightshade (Solanum malacoxylon Send.)
on calcium metabolism in livestock. In: Childers NF,
Russo GM (eds.). The nightshades and health. New
Jersey: Horticultural Publications, 1986; 144-157
N.F. M.S. Margoles. "An Apparent Relation of
Nightshades (Solanaceae) to Arthritis" Journal of
Neurological and Orthopedic Medical Surgery (1993)
RS, Carter RL, Katz P, Kowsari B, Longley S, Finnie
S. Diet therapy for rheumatoid arthritis. Arthritis
Sköldstam L. Fasting and vegan diet in
rheumatoid arthritis. Scand J Rheumatol
A. Food and Our Bones. New York, NY: Penguin Putnam
9) Haugen M,
Kjeldsen-Kragh J, Nordvåg B-Y, Førre
Ø. Diet and disease symptoms in rheumatic
diseases—Results of a questionnaire based survey.
Clin Rheumatol 1991;10:401–7.
10) Babu, B.
N. Harish, P. A. Mahesh. Y. P. Venkatesh. A
cross-sectional study on the prevalence of food
allergy to eggplant (Solanum melongena L.) reveals
female predominance. Clinical & Experimental
Allergy 38(11):1795–1802, 2008.
S, Kolarich D, Foetisch K, Lauer I, Altmann F, Conti
A, et al. Molecular characterisation and allergenic
activity of Lyce2 (beta-fructofuranosidase), a
glycosylated allergen of tomato. Eur J Biochem
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