The bioavailability of minerals is poor in legumes

This paper was published in the British Journal of Nutrition 2002 Dec;88 Suppl 3:S281-5

Study title and author:
Bioavailability of minerals in legumes.

Sandberg AS.
Department of Food Science, Chalmers University of Technology, PO Box 5401, SE 402 29 Göteborg, Sweden. ann-sofie.sandberg@fsc.chalmers.se

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/12498628

Professor Ann-Sofie Sandberg is head of the Life Science Division at Chalmers University of Technology, Göteborg, Sweden. She has an extensive record in the field of phytate/bioavailability of minerals, food processing/bioavailability of nutrients and in the development of analytical methods for measuring nutrients and bioactive compounds.

Professor Sandberg reviewed the scientific evidence regarding the bioavailability of minerals in legumes.

Professor Sandberg found:
(a) The content of iron and other minerals is generally high in legumes. However, the legumes also contain antinutritional factors, such as proteinase inhibitors, lectin, raffinose oligosaccharides, saponins, polyphenols and phytate. Antinutritional factors lower the nutritional value of a food by lowering the digestibility or bioavailability of nutrients.
(b) Phytate is a well-known inhibitor of absorption of essential dietary minerals such as non-haem iron, zinc and calcium. 
(c) Some polyphenols are potent inhibitors of non-haem iron absorption.
(d) In the modern food industry, the high phytate content of soya-based infant formulas is of concern as low zinc absorption from a soya-protein-based infant formula has been found.
(e) Soya protein per se has an inhibiting effect on iron absorption.
(f) In many developing countries where diet is based on cereal and legume products, deficiency of iron and zinc, is highly prevalent.
(g) In developing countries iron deficiency, due to poor bioavailability, retards normal brain development in infants and affects the success of a pregnancy by increasing premature deliveries, as well as increased disease of mother and child at or around childbirth.
(h) Zinc deficiency prevents normal child growth and greatly weakens the immune system, leading to more infections.
(i) In industrialised countries where diet is based on cereal and legume products, deficiency of iron and zinc, is highly prevalent in certain groups such as women of fertile age, infants, adolescents and vegetarians.

The review finds that the bioavailability of minerals is poor in legumes and may lead to adverse health consequences.

Diets high in bran decrease iron absorption by over 90%

This study was published in the American Journal of Clinical Nutrition 1989 Mar;49(3):542-5

Study title and authors:
Iron absorption: no intestinal adaptation to a high-phytate diet.

Brune M, Rossander L, Hallberg L.
Department of Medicine II, University of Göteborg, Sweden.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/2538051

Brune notes that several studies have shown that bran (and its high phytate content) inhibits the absorption of iron in man.

The present study examined the possibility that a high bran and phytate intake over a long period would induce adaption in the intestines or its microflora leading to a reduction of the inhibitory effect of dietary phytates on iron absorption. Such changes might occur in vegetarians and populations in developing countries with a usually very high dietary intake of phytates. The study included 13 dedicated vegetarians or vegans who had had a high phytate intake for around 25 years who were compared with six subjects who had a normal unrestricted diet.

The effect of bran on iron absorption was studied by comparing iron absorption from wheat rolls (i) with bran and (ii) without bran in both the vegetarian and non-vegetarian groups.

The study found:
(a) The bran rolls had a large inhibitory effect on iron absorption in both vegetarians and non-vegetarians.
(b) The effect was almost identical in both groups (93% inhibition in the vegetarian group and 92% in the non-vegetarian group) even though the vegetarians had had a very high phytate intake for a long time and the non-vegetarians had a much lower phytate intake.
(c) It can be concluded that no adaption could be observed among the vegetarians despite their high phytate intake.

The study concludes that the fact their is no intestinal adaptation to a high phytate intake has wide nutritional implications, and that a diet with a high phytate content must always be considered to impair iron absorption even if phytate intake has been high for several years.

Fibre rich diet results in zinc, copper and magnesium deficiencies

This study was published in the Journal of the Trace Elements in Medicine and Biology 1996 Jun;10(2):68-76

Study title and authors:
Zinc, copper and magnesium absorption from a fibre-rich diet.

Knudsen E, Sandström B, Solgaard P.
Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/8829129?dopt=Abstract

This study investigated the effect of a high-fibre and high-phytate diet on levels of zinc, copper and magnesium. The study lasted for 21 days and included eight healthy subjects who were given a diet of conventional foods that included 1 mmol phytic acid, 29 g dietary fiber, 140 mumol zinc, 13 mumol copper, and 9 mmol magnesium per 2,415 calories.

The study found:
(a) The subjects levels of zinc decreased by 7 mumol.
(b) The subjects levels of copper decreased by 5 mumol.
(c) The subjects levels of magnesium decreased by 3 mmol.

The study reveals that a fibre-rich diet is associated with a net loss of the nutrients zinc, copper and magnesium.

Addition of chicken liver to rice or maize based meals, results in large increases of bioavailable iron and zinc

This post includes a synopsis of a study published in Maternal and Child Nutrition 2005 Oct;1(4):263-73 and a recipe for chicken liver spread.

Study title and authors:
Household dietary strategies to enhance the content and bioavailability of iron, zinc and calcium of selected rice- and maize-based Philippine complementary foods.
Perlas LA, Gibson RS.
Food and Nutrition Research Institute, Department of Science and Technology, Bicutan, Taguig, Metro Manila, Philippines. lap@fnri.dost.gov.ph

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/16881908

Books:

Perlas notes that Philippine foods are predominantly plant-based, with a low content of readily available iron, zinc, and calcium, and a relatively high amount of phytate, which is a potent inhibitor of mineral absorption.

The study compared the iron, zinc, and calcium content, and estimated iron and zinc bioavailability of rice- and maize-based Filipino foods prepared in various ways. (i) with soaking. (ii) without soaking (iii) and/or enrichment with chicken liver, egg yolk, small soft-boned fish, and mung bean grits.

The study revealed:
(a) Addition of chicken liver, followed by egg yolk, resulted in the greatest increases in iron and zinc content for both the rice- and maize-based foods.
(b) Addition of small dried fish with bones had the greatest effect on calcium.
(c) Phytates were reduced by soaking.

Perlas concludes: Enrichment with animal protein or soaking has the potential to enhance the content of absorbable iron, zinc, and probably calcium to varying degrees in rice- and maize-based Philippine foods.

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Recipe of the day

Chicken liver Spread

Ingredients:

Chicken Livers

1 1/2 lbs. of chicken livers, trimmed
1 large yellow onion, chopped
2 cloves of garlic, peeled and sliced
1 stick of butter
3/4 cup of dry white wine, or dry vermouth
2 hard cooked eggs, quartered
1 tbsp. of dry sherry or brandy
1 big handful of parsley, washed and coarsely chopped
several grinds of black pepper, more is better
1 and 1/2 teaspoons of coarse salt
1/2 teaspoon of freshly grated nutmeg
pinch of allspice
pinch of cumin
minced chives for garnish

Instructions:
In a saucepan, heat 1/2 stick of butter just to the sizzle stage, add livers, onion, garlic and wine.

Cover pan and reduce heat to low and poach the livers 20 minutes or so.

You want them cooked and moist, not dry. The onions and garlic should be soft but not brown.

In a food processor, process the livers and pan juices until coarsely chopped.

Add parsley, eggs, brandy, seasonings, remaining 1/2 stick of butter (softened, not melted).

Process until as smooth as you want.

Taste and adjust for salt. You want to overseason a little because then it chills the flavors tend to mellow out.

Chicken Liver Spread



Oat bran and oat porridge markedly inhibit the absorption of non-haem iron

This post includes a summary of a paper published in the European Journal of Clinical Nutrition 1990 Nov;44(11):783-91 and a recipe for butter chicken in a silky sauce.

Study title and authors:
Inhibitory effect of oat products on non-haem iron absorption in man.

Rossander-Hulthén L, Gleerup A, Hallberg L.

Books:

Department of Medicine, University of Göteborg, Sahlgren's Hospital, Sweden.

This paper can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/2086207

In this review Rossander-Hulthén finds that oat bran and oat porridge markedly inhibited the absorption of non-haem iron. The inhibition can be explained by the high phytate content of oat products.

Rossander-Hulthén concludes: The inhibitory effect of oat products on iron absorption is sufficiently marked to be a serious consideration if such products are more regularly consumed.

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Recipe of the day

Butter Chicken in a Silky Sauce

Ingredients:

Food Mall: Chicken Thighs

■4 pounds chicken thighs, chopped into 1-inch cubes

■6 garlic cloves, crushed
■2 teaspoons garam masala
■3 teaspoons ground coriander
■3 teaspoons ground cumin
■1 teaspoon chilli powder
■1 teaspoon paprika
■3/4 cup Greek-style (thick) yogurt
■7 tablespoons butter, chopped1 tablespoon white vinegar
■3 tablespoons tomato paste
■4 large tomatoes, peeled and chopped
■6 cardamom pods (crush pods slightly to release seeds and more flavor)
■1 cinnamon stick
■1 1/2 cup cream or coconut milk
■1/2 cup fresh coriander, coarsely chopped

Instructions:
Combine chicken, garlic, spices and yogurt in a covered container. Refrigerate for an hour or two.

Melt butter in a deep pan. Add vinegar, tomato paste, tomatoes, cardamom and cinnamon. Boil rapidly, stirring until sauce is thick (approximately 20 minutes).

Reduce heat to a simmer and add chicken. Continue to simmer, stirring occasionally until chicken is cooked through. Add cream or coconut milk, simmer a few minutes more, and garnish with chopped cilantro.

Butter Chicken in a Silky Sauce

Dietary phytates and tannins may lead to iron deficiency

This post includes a synopsis of a paper published in the American Journal of Public Health 1998 Apr;88(4):576-80 and a recipe for grilled steaks.

Study title and authors:
Deficient dietary iron intakes among women and children in Russia: evidence from the Russian Longitudinal Monitoring Survey.

Books:

Kohlmeier L, Mendez M, Shalnova S, Martinchik A, Chakraborty H, Kohlmeier M.

Department of Epidemiology, University of North Carolina at Chapel Hill 27599-7400, USA.

This paper can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/9550997

The study of 10,548 women and children evaluated the iron sufficiency of the Russian diet.

The study found:
(a)  Dietary iron intakes were deficient in the most vulnerable groups: young children and women of reproductive age.
(b) Poverty status was strongly associated with deficiency.
(c) Grain products rich in phytates, (which inhibit iron absorption), were the major food source of iron in Russia.
(d) High intakes of tea rich in tannins, also inhibited iron bioavailability.

To conclude: The dietary data suggests that Russian women and children are at high risk of iron deficiency. Since changes in eating behavior could potentially double iron bioavailability, (consuming less grain and less tea), educational programs should be explored as a strategy for improving iron nutriture.

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Recipe of the day

Easy Grilled Steaks

Ingredients:

Food Mall: Rib-Eye Steak

Rib-Eye Steak

Instructions:
As many steaks as you will need to feed your family, bring to room temperature, sprinkle each side with sea salt and freshly cracked black pepper and grill over medium high heat. We like our steak rare to medium rare so for thinner cuts of meat it only takes about 5 min. per side on the grill. Let your meat rest for at least 10-15 minutes before you slice into it so that you do not lose all those precious juices.

Grilled Steaks

Increased dietary fiber intake decreases the availability of nutrients for the body

This post includes a summary of a paper published in the American Journal of Clinical Nutrition January 1978 vol. 31 no. 1 142-159 and a recipe for smoky skirt steak.

Study title and author:
A review of research on effects of fiber intake on man
June L. Kelsay, Ph.D.
 
This paper can be accessed at: http://www.ajcn.org/content/31/1/142.full.pdf+html
 

Books:

Phytic acid is a naturally forming component found in plant fiber in a wide range of plant foods, including wheat bran, whole grain, and legumes. Nuts and seeds also contain phytic acid, but in smaller amounts compared to bran and grains.

 
In this review of the research on the effects of fiber intake on man Kelsay found:
(a) Some reports indicate that fiber in the diet may lower serum levels of calcium and iron
(b) Energy, fat, nitrogen, and mineral absorption appear to be decreased by increased fiber intake.

To conclude: Increased dietary fiber intake decreases the availability of nutrients for the body.

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Recipe of the day

Food Mall: Skirt Steak

Smoky Skirt Steak

Ingredients:

◦2 1/2 lbs. skirt or flank steak

◦4 T smoked paprika
◦1 t salt
◦1 t pepper

Method:
Rub the ingredients on both sides of the steak. Place on a preheated grill and let cook for about 12 minutes…that’ll get you a nice medium rare.

Smoky Skirt Steak



Dietary phytates lead to iron deficiency and anemia

This post includes a synopsis of a study published in the International Journal of Food Sciences and Nutrition 2009;60(1):51-9 and a recipe for lamb and asparagus.

Study title and authors:
Influence of dietary and socio-demographic factors on the iron status of married adolescent girls from Indian urban slums.
Tupe R, Chiplonkar SA, Kapadia-Kundu N.
Agharkar Research Institute, G G Agarkar Road, Pune, India.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/18608535

The study explored the influence of dietary factors of iron bioavailability in 173 married adolescent girls in India.

The prevalence of iron deficiency was 25.1%, and anemia was seen in 46.4%  of the girls.

The study found a diet high in phytates resulted in the low bioavailable iron intakes.

                                                                                                                                             Books:

High concentrations of phytates occur in the following foods:
•Most whole grain cereal foods (wheat, rye, rice, oats)

•Nuts and seeds (pumpkin, sunflower)

•Soybeans, other types of beans

•Potatoes

•Artichokes

•Blackberries

•Broccoli
•Carrots
•Figs
•Strawberries

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Recipe of the day

Lamb and Asparagus
                                                                                                                    Food Mall: Boneless Lamb

Ingredients:

• 1 chopped red onion

• 3 garlic cloves crushed

• 1/2 c of dry white wine

• 3 c of steamed sliced asparagus

• 1 1/2 lb boneless lamb chopped into small cubes

• Freshly-ground black pepper to taste

Instructions:

Steam asparagus. Heat a large frying pan and add 1/2 of the wine. Bring to the boil and add the onion and garlic, cook until softened.

Add the lamb and cook for about 6 minutes.

Add the rest of the wine and the asparagus. Cover and cook for about 10 minutes, until lamb is tender.

Pepper to taste.

Iron deficiency attributed to inadequate intakes of flesh foods combined with high intakes of dietary fiber, phytate, and tannins that inhibit absorption of dietary iron

This post includes a summary of a paper published in the American Journal of Clinical Nutrition Vol 44, 643-652 and a recipe for veal, carrot and chestnut ragout.

Books:

Study title and authors:

Iron status of predominantly lacto-ovo vegetarian East Indian immigrants to Canada: a model approach
GS Bindra and RS Gibson

This paper can be accessed at: http://www.ajcn.org/cgi/content/abstract/44/5/643
 
In summary, the high prevalence of iron deficiency noted in this study was attributed to inadequate intakes of readily available dietary iron from flesh foods combined with high intakes of dietary fiber, phytate, and tannins that inhibit absorption of dietary iron.
 
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Recipe of the day

Veal, Carrot and Chestnut Ragout

Ingrediets:

Food Mall: Veal Stew Meat

18 fresh chestnuts
2 1/2 pounds veal stew meat, cut into 2x1-inch pieces

4 tablespoons olive oil
1 1/2 cups chopped onion
1 1/2 tablespoons chopped garlic
1 bay leaf
2 1/2 cups canned low-salt chicken broth
3/4 cup dry white wine
6 medium carrots, peeled, cut into 1-inch pieces
3 tablespoons chopped fresh sage

Instructions:
Preheat oven to 400 deg. F. Using small sharp knife, cut an X in each chestnut. Place in roasting pan. Bake until tender and shells loosen, about 35 minutes. Cool slightly. Remove hard shell and papery brown skin from each nut. Set nuts aside.

Pat veal pieces dry with paper towels. Sprinkle with pepper. Heat 2 tablespoons oil in heavy large pot over medium-high heat. Working in batches, add veal to pot and cook until brown on all sides, about 10 minutes. Using slotted spoon, transfer veal to large bowl.

Heat 2 tablespoons oil in same pot. Add onion, garlic and bay leaf. Reduce heat to medium; cover and cook until onion is tender, stirring occasionally, about 5 minutes. Stir in broth and wine. Add veal and any accumulated juices from bowl. Bring to boil. Reduce heat. Cover; simmer 45 minutes, stirring occasionally.

Add carrots to stew. Cover and cook until carrots are almost tender, about 25 minutes. Uncover and cook until meat is very tender and liquid is reduced to thin sauce consistency, about 25 minutes longer. Stir in nuts and sage. Simmer until nuts are heated through, about 3 minutes. Discard bay leaf. Transfer ragout to bowl.

Veal, Carrot and Chestnut Ragout