Potatoes

Kimia

Tell me about potatoes. Are they good for you? They are low in calories and make me full so I'm thinking they are good. And I remember El D saying something about their skin or something being brilliant (i could be remembering this wrong).

I love potatoes.

stacexD

The skin is full of fibre and all the good stuff in potatoes

Blatter

I wouldn't say they're low in calories by any means. I like potatoes but Jesus it's easy to eat way too many of them.

EdoErgoSum

Potatoes

Let’s first examine potatoes. Potatoes generally maintain one of the highest glycemic index and load values of any food3-6. Regular consumption of high glycemic index carbohydrates may promote obesity and diseases of insulin resistance, including type 2 diabetes, cardiovascular disease, abnormal blood lipids, gout, acne, polycystic ovary syndrome, epithelial cell cancers (breast, colon and prostate), acanthosis nigricans (a skin disease), and male vertex balding7. Consequently in both of my books I do not recommend that potatoes be included as a regular component of Paleo Diets. Additionally, as you can see from Table 1, most of the potatoes consumed in the U.S. are highly processed in the form of french fries, mashed potatoes, dehydrated potato products, and potato chips. Processed potato foods typically are made with multiple additives (salt, vegetable oils, trans fats, refined sugars, dairy products, cereal grains, preservatives, and other food additives) that may adversely affect health in a variety of ways.

An additional nutritional property of potatoes that is rarely considered in regard to human health is their saponin content. Saponins derive their name from their ability to form "soap" like foams when mixed with water. Chemically, saponins are classified as either steroid glycosides or triterpenoid glycosides. A glycoside is any of a group of organic compounds occurring abundantly in plants that yield a sugar and one or more non-sugar substances upon hydrolysis (chemical decomposition in which a compound is split into other compounds by reacting with water). Steroid glycosides are commonly called glycoalkaloids.

Both categories of saponins are widely distributed throughout the plant kingdom including many cultivated crops. The primary function of saponins is to protect the plant from microbial and insect attack by dissolving cell membranes of these potential predators8. In mammals, including humans who consume saponin containing plants, these substances frequently create pores in the gut lining, thereby increasing intestinal permeability8-10. If they enter the bloodstream in sufficient concentrations, they cause hemolysis (destruction of the cell membrane) of red blood cells8-10.

Figure 1 shows how saponins disrupt cell membranes which may lead to a leaky gut. Saponins first bind cholesterol molecules in intestinal cell membranes due to the affinity of a saponin component (the aglycone moiety) for the membrane sterol (cholesterol)9. In the series of steps that follows, you can see how saponins cause portions of the cell membrane to buckle and eventually break free, forming a pore or a hole in the membrane.

Figure 1. The proposed mechanism by which dietary saponins may elicit pores in intestinal cells leading to a "leaky gut" (adapted from 9).


Potatoes contain two glycoalkaloid saponins: ?-chaconine and ?-solanine which may adversely affect intestinal permeability and aggravate inflammatory bowel disease11, 12. Even in normal healthy adults, a meal of mashed potatoes results in the rapid appearance of both ?-chaconine and ?-solanine in the bloodstream13. The toxicity of these two glycoalkaloids is dose dependent – meaning that the greater the concentration in the bloodstream, the greater is their toxic effect. At least 12 separate cases of human poisoning from potato consumption, involving nearly 2000 people and 30 fatalities have been recorded10. Potato saponins can be lethally toxic once in the bloodstream in sufficient concentrations because these glycoalkaloids inhibit a key enzyme (acetyl cholinesterase) required for the synthesis of acetylcholine, a neurotransmitter required for nerve impulse conduction10. The concentration of both ?-chaconine and ?-solanine in a variety of potato foods are listed in Table 3. Note that the highest concentrations of these toxic glycoalkaloids appear in potato foods containing the skins.

Table 3. Concentrations (mg/kg) of total glycoalkaloids (?-chaconine + ?-solanine) in a variety of potato foods (adapted from 10).

Food Item ?-chaconine + ?-solanine (mg/kg)
Fried skins 567-1450
Chips with skins 95 - 720
Chips (US potatoes) 23 - 180
Frozen baked potatoes 80 - 123
Frozen skins 65 - 121
Baked potato w/jacket 99 - 113
Dehydrated potato flour 65 - 75
Boiled peeled potato 27 - 42
Canned whole new potatoes 24 - 34
Frozen fried potato 4 - 31
Frozen French fries 2 - 29
Dehydrated potato flakes 15 - 23
French fries 0.4 - 8
Frozen mashed potatoes 2 - 5
Canned peeled potato 1 - 2

So the next logical question arises: Should we be eating a food that contains two known toxins which rapidly enter the bloodstream, increase intestinal permeability and potentially impair the nervous system?

In the opinion of these authors: ". . . if the potato were to be introduced today as a novel food it is likely that its use would not be approved because of the presence of these toxic compounds." 11

Other researchers state: "Available information suggest that the susceptibility of humans to glycoalkaloids poisoning is both high and very variable: oral doses in the range 1 - 5 mg/kg body weight are marginally to severely toxic to humans whereas 3 - 6 mg/kg body weight can be lethal. The narrow margin between toxicity and lethality is obviously of concern. Although serious glycoalkaloid poisoning of humans is rare, there is a widely held suspicion that mild poisoning is more prevalent than supposed." 10

The commonly accepted safe limit for total (?-chaconine + ?-solanine) in potato foods is 200 mg/kg, a level proposed more than 70 years ago, whereas more recent evidence suggests this level should be lowered to 60 – 70 mg/kg10. If you take a look at Table 2 you can see that many potato food products exceed this recommendation.

I believe that far more troubling than the potential toxicity of potato glycoalkaloids is their potential to increase intestinal permeability over the course of a lifetime, most particularly in people with diseases of chronic inflammation (cancer, autoimmune disease, cardiovascular disease and diseases of insulin resistance). A leaky gut has been recently proposed to be a universal initiating trigger for autoimmune diseases14 – a conclusion that I agree with15, as well as promoting cardiovascular disease16, 17 and diseases of insulin resistance18. When the gut becomes "leaky" it is not a good thing, as the intestinal contents may then have access to the immune system which in turn becomes activated thereby causing a chronic low level systemic inflammation known as endotoxemia16 – 18. In particular a component of the cell walls of gut gram negative bacteria called lipopolysaccharide (LPS) is highly inflammatory. Any LPS which gets past the gut barrier is immediately engulfed by two types of immune system cells (macrophages and dendritic cells). Once engulfed by these immune cells, LPS binds to a receptor (toll-like receptor-4) on these cells causing a cascade of effects leading to increases in blood concentrations of pro-inflammatory cytokines (localized hormones) including interferon gamma (INF-?),interleukin 1 (IL-1), IL-6, IL-8 and tumor necrosis factor alpha (TNF-?)16, 19. Two recent human studies have shown that high potato diets increase the blood inflammatory marker IL-620, 21. Without chronic low level systemic inflammation, it is unlikely that few of the classic diseases of civilization (cancer, cardiovascular disease, autoimmune diseases and diseases of insulin resistance) would have an opportunity to take hold and wreak their fatal effects.

A final note on potatoes – to add insult to injury, this commonly consumed food is a major source of dietary lectins. On average potatoes contain 65 mg of potato lectin per kilogram. As is the case with most lectins, they have been poorly studied in humans, so we really don’t have conclusive information how potato lectin may impact human health. However, preliminary tissue studies indicate that potato lectin resists degradation by gut enzymes, bypasses the cell wall barriers and can then bind various tissues22, 23. Potato lectins have been found to irritate the immune system and produce symptoms of food hypersensitivity in allergenic and non-allergenic patients24. Just say "no" to potatoes!!

Q: Hi, the Paleo Diet makes a lot of sense to me and I very much appreciate the research that's gone into it. However, am I right in thinking that any diet we are adapted to may nevertheless not be an ideal diet? We adapted to a diet that enabled us to be healthy enough to live long enough to reproduce healthy enough offspring.

If I understand correctly, couldn't certain foods could make that basic diet even healthier? For example, I have The Paleo Diet for Atheletes out from the library right now and I see that you believe that the life of an athlete requires departure from a strict paleolithic diet. Couldn't properly treated grains and legumes be beneficial additions to the diet? (i.e. soaked/sprouted to reduce/eliminate anti-nutrients?)

I am waiting to receive The Paleo Diet from the library (I'm on a long waiting list, which is good news I guess!) so maybe you address this issue in the book, in which case, I apologise. But if not, I would appreciate knowing your views on soaking/sprouting grains and legumes, and the reasons behind those views.

Thanks so much,
Zena

A: Dear Zena, first of all - thanks for supporting our work.

Lectins, one of the known antinutrients in cereal grains and legumes1, have been demonstrated to exert several deleterious effects upon human physiology1, (especially for those with autoimmune diseases) by increasing intestinal permeability2. Their function is to protect the plant against attacks by plant-eating animals by using several toxic substances, such as lectins3. There is a growing body of evidence showing that both the root and the sprout of wheat kernels have significant amounts of wheat germ agglutinin (WGA), one of the most studied lectins. Indeed, WGA originates in the wheat kernel, especially during germination and growth4, and the highest concentrations are found in young plant roots, seeds, and sprouts.

Lectins are resistant to digestive enzymes, and are found intact in peripheral circulation, as shown by Wang et al (1998)5. Furthermore, they are deposited in the internal organs6.

As stated by Pusztai et al7, lectins are heat stable, and normal cooking does not completely eliminate these toxic compounds unless they are pressur cooked8-11. The best way to reduce lectins' adverse health effects is to limit their intake.

In addition, saponins - another type of toxic/antinutritive compound - exist in legume sprouts. Saponins have been shown to affect the gut barrier and by extension immune system function12. They may also increase the risk of autoimmune diseases in genetically susceptible individuals13. Soaking, sprouting or cooking legumes, does not reduce their saponin content14, 15.

In addition, a peptide fraction from gluten proteins called gliadin is found in wheat. Gliadin is resistant to digestive enzyme degradation16, arrives intact when it comes into contact with intestinal epithelial cells17, and increases intestinal permeability. Increased intestinal permeability may be at the root of autoimmune diseases such as Celiac Disease and Type 1 Diabetes13.

Phytate, the main form of phosphorus storage in many plants (especially bran and seeds) is classified as an antinutrient because is a chelator of iron, magnesium, calcium and zinc1. Phytate ingestion inhibits the intestinal absorption of those minerals. Phosphorus from phytate is unavailable to humans, as we do not produce the phytase enzyme necessary to break down phytate - unlike ruminants, who do produce phytase, and are able to digest phytate18. Yeast fermentation in bread reduces phytate content19. Furthermore, addition of ascorbic acid counteracts the inhibitory effects of phytate upon iron absorption20. Soaking and fermentation reduces the phytate content of grains and legumes as indicated in several studies21, 22, 23, 24.

Having said that, Dr. Cordain in his first book talks about the 85:15 rule, where he explains that 85% of caloric intake from modern paleolithic-like foods is still more healthy than the typical western diet, where more than 70% of caloric intake comes from foods introduced in the human food chain after the agricultural revolution25.

The bottom line is that our metabolism is perfectly adapted to the nutrition that shaped our genome during million of years of evolution. Therefore, any nutrient introduced after the agricultural revolution may not be compatible with our ancient genome. We believe that anyone engaged in athletic activities could do very well on a diet based on 85% paleolithic nutrients, which are preferable to the nutrients found in the typical western diet.

I hope this is helpful.
Maelán Fontes

References:

1. Cordain L. Cereal Grains: Humanity’s Double-Edged Sword. World Rev Nutr Diet. Basel, Karger, 1999, vol 84, pp 19–73.
2. Cordain L. et al. Modulation of immune function by dietary lectins in rheumatoid arthritis. British Journal of Nutrition (2000), 83, 207–217.
3. Chrispeels, M.J. & Raikel, N.V. (1991) Lectins, lectin genes, and their role in plant defense. Plant Cell 3, 1-9.
4. Miller, R., & Bowles, D. (1982). A comparative study of the localization of wheat-germ agglutinin and its potential receptors in wheat grains. Biochem. J., 206, 571-576.
5. Wang Q, Yu LG, Campbell BJ, Milton JD, Rhodes, JM. Identification of intact peanut lectin in peripheral venous blood. Lancet 1998;352:1831-32.
6. Caron, M. & Steve, A.P. (2000) Lectins and Pathology, Taylor & Francis, London.
7. Pusztai A and Grant G. Assessment of lectin inactivation by heat and digestion. From Methods in Molecular Medicine. Vol 9 Lectin methods and protocols. Edited by J M Rhodes and J D Milton Humana Press Inc. Totowa, NJ.
8. Grant G, More LJ, McKenzie NH, Pusztai A. The effect of heating on the haemagglutinating activity and nutritional properties of bean (Phaseolus vulgaris) seeds. J Sci Food Agric 1982;33: 1324-1326.
9. Boufassa C, Lafont J, Rouanet J M, Besancon P 1986 Thermal inactivation of lectins (PHA)isolated from Phaseolus vulgaris. Food Chem 20 295-304.
10. Buera M P, Pilosof A M R, Bartholomai G B 1984 Kinetics of trypsin inhibitory activity loss in heated flour from bean Phaseolus vulgaris. J Food Sci 49 124-126.
11. Collins J L, Beaty B F 1980 Heat inactivation of trypsin inhibitor in fresh green soybeans and physiological responses of rats fed the beans. J Food Sci 45 542-546.
12. Patel B, Rober S, Sporns P, et al. potato glycoalkaloid adversely affect intestinal permeabiliry and aggravate inflammatory bowel disease.
13. Visser J, Rozing J, Sapone A et al. Tight junctions, Intestinal permeability and Autoimmunity. Ann. N. Y. Acad. Sci. 1165: 195-205 (2009).
14. Ruiz RG, Price K, Rose M, Rhodes M, Fenwick R. A preliminary study on the effect of germination on saponin content and composition of lentils and chickpeas. Z Lebensm Unters Forsch 1996;203:366-369.
15. Ruiz RG, Price KR, Arthur AE, Rose ME, Rhodes MJ, Fenwick RG. Effect of soaking and cooking on the saponin content and composition of chickpeas (Cicer arietinum) and lentils (Lens culinaris). J Agric Food Chem 1996;44:1526-1530.
16. Shan L, Qiao SW, Arentz-Hansen H, et al. Identification and Analysis of Multivalent Proteolytically Resistant Peptides from Gluten: Implications for Celiac Sprue. J Proteome Res. 2005 ; 4(5): 1732–1741.
17. Drago S, Asmar R, Di Pierro M, et al. Gliadin, zonulin and gut permeability: Effects on celiac and
18. non-celiac intestinal mucosa and intestinal cell lines. Scandinavian Journal of Gastroenterology, 2006; 41:408/419.
19. Klopfenstein, TJ et al. "Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution". Council for Agricultural Science and Technology 21.
20. Reinhold JG. Phytate destruction by yeast fermentation in whole wheat meals. J Am Diet Assoc 1975;66:38-41.
21. Hallberg L, Brune M, Rossander L. Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate. Am J Clin Nutr 1989;49:140-4.
22. Chen LH, Pan SH. Decrease of phytates during germination of pea seeds (Pisium Sativa). Nutr Rept Int. 1977;16: 125-131.
23. Walker KA. Changes in phytic acid and phytase during early development of phaseoleus vulgaris beans. Planta 1974;116:91-98
24. Bain, J. M., Murcer, F. V.: Changes in phytic acid and acid-soluble phosphorus in maturing pinto beans. J. Sci. Fd. Agric. 20, 82–84 (1966).
25. Jennings, A. C., Morton, R. K.: Changes in nucleic acids and other phosphorus-containing compounds of developing wheat grain. Aust. J. Biol Sci. 16, 332–341 (1963b).
26. Cordain L, Eaton SB, Sebastian A, et al. Origins and evolution of the western diet: health implications for the 21st century. Am J Clin Nutr 2005;81:341–54.

Source:

http://www.rawpaleodietforum.com/infonews-items/cordain-newsletter-update/msg34892/#msg34892

boomtown84

^^^ = riveting stuff!:rolleyes:
Op- potatoes are great and if you are irish you'll probably die sooner if you don't eat them.

El_Dangeroso

Oh lord! Potatoes do NOT give you leaky gut! Maybe if you injected them into your bloodstream. People, do NOT inject potatoes into your bloodstream, don't do it!

All plants contain scary sounding chemicals, but potatoes have been bred by humans to vastly reduce saponin content. Also then there's the slightly hormetic effect of low level exposure to toxins that is actually beneficial (that's how polyphenols work).

Potatoes are good eating, apparently they are the most filling of any starch. If your super-worried about saponins, peel them as 90% of the saponins are in the skin.

orangebud

The potato is an incredibly healthy food that has gotten a bad reputation, largely
because it can be prepared in ways that counteract its benefits. Baked and served in
its skin, a potato is a surprisingly good source of vitamin C, as well as potassium,
fiber, vitamin B6 and other B vitamins, copper, manganese, and even some lutein.
The key to getting the benefits of potatoes is to eat them baked rather than
fried. But if you are absolutely having a French fry craving, go ahead and LIVIT—
enjoy a few to satisfy the craving and to help prevent overloading on them when the
craving gets out of control.

nutritional composition One medium-large potato with skin provides 220 calories,
51 g carbohydrate, 4.6 g protein, 4.8 g dietary fiber, 26 mg vitamin C, 3.3 mg niacin,
22 mcg folic acid, 1.12 mg pantothenic acid, 844 mg potassium, 16 mg sodium,
115 mg phosphorus, 20 mg calcium, 2.75 mg iron, and 55 mg magnesium.

EdoErgoSum

do you have any info on bioavailability of nutrient in potatoes?

Sir Digby Chicken Caesar

is baked healthier than steamed?

corkcomp

Baked / Steamed it makes no difference IMO.. One big potato isnt that high in calories and can be very filling.. I cook them in the microwave, about 4 or 5minutes wrapped in kitchen paper. They take rediculously long in a normal oven:rolleyes: One thing to watch is that potatoes are like sponges, one could easily soak 100g of butter so use low calorie additions if watching calorie content.

RandolphEsq

Is sweet potato the same or better/worse?

boomtown84

RandolphEsq wrote: »

Is sweet potato the same or better/worse?

none of the above.....it's just different.mix 'em together.

corkcomp

RandolphEsq wrote: »

Is sweet potato the same or better/worse?

depends what you mean by "better", they do pack more nutrients but eating the skin isnt really an option like normal potatoes

Kimia

I love sweet potatoes. Would they be a good nutritious option? I know green and leafy is the best of all but my god it gets old sometimes eating rabbit food.

El_Dangeroso

Sweet potatoes have more beta-carotene. They do a number on my digestion and they taste horrible IMO so I avoid.