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Australian Dietary Guidelines submission

ID: 
73
Personal Details
Organisation Name: 
Solae, LLC
Online comments
Specific comments: 
Chapter 1- Introduction

Solae, LLC appreciates the opportunity to respond to The National Health and Medical Research Council (NHMRC) notice for written comments to the Australian Dietary Guidelines and Australian Guide to Healthy Eating.  Solae is dedicated to providing high quality soy protein ingredients that are consumed by millions of people around the world.   As a leader in food and ingredient product development, and nutrition science research for the last 50 years, Solae supports the use of a science-based process to develop the Guidelines. Solae acknowledges the effort put forth by NHMRC in evaluating the current nutrition science and for the resources used to prepare this comprehensive report that will be used to develop the Australian Dietary Guidelines and Australian Guide to Healthy Eating.

One of the dietary patterns identified by the NHMRC as consistent with the Guidelines and associated with reduction in all-cause and cardiovascular mortality is an increased intake of plant-based foods.  We commend the NHMRC for acknowledging the health benefits associated with consuming a plant-based diet.  The high quality protein from soy can give people a plant-based protein choice, which fits well into the Guidelines recommendations.  Soy foods are particularly important because they:

  • provide high quality protein that is comparable to animal proteins, yet more sustainable;
  • are typically low in saturated fat and cholesterol-free; and
  • can be a good source of fiber
  • can be easily incorporated into the diet, as well as serve as a nutritious substitute for foods higher in saturated fat and cholesterol

Unequivocal data generated during the past 25 years have shown that soy foods provide nutritionally complete protein based on the soybean’s indispensable amino acid spectrum.  The 2012 Australian Dietary Guidelines should clearly state that soy protein is the only widely available high quality complete vegetable protein shown to maintain nitrogen balance when fed as the sole protein source at minimum recommended intake levels1-6. The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) Joint Expert Consultation’s Protein Quality Evaluation Report7 recommended the protein digestibility-corrected amino acid score (PDCAAS), which is a scientific and rational procedure for assessing protein quality.  The protein digestibility-corrected amino acid score (PDCAAS) of isolated soy protein and soy protein concentrate achieves the maximum value of 1.00 and meets all published estimates for the essential amino acid requirements of children and adults8-11. Isolated soy protein achieves 97% digestibility11, similar to other high quality “animal” protein sources (milk, meat and egg) which achieve between 94-97%.  Soy protein is the only widely available high quality complete vegetable protein and is comparable to meat, milk and egg protein12-14.  Therefore, we suggest that soy protein be recognized as a high quality protein and the 2012 Guidelines should make this distinction.

References

1.  Zezulka AY, Calloway DH. Nitrogen retention in men fed isolated soybean protein supplemented with L-methionine, D-methionine, N-acetyl-L-methionine, or inorganic sulfate.  J Nutr. 1976 Sep;106(9):1286-91.

2.  Istfan N, Murray E, Janghorbani M, Young VR. An evaluation of the nutritional value of a soy protein concentrate in young adult men using the short-term N-balance method.  J Nutr. 1983 Dec;113(12):2516-23.

3.  Scrimshaw NS, Wayler AH, Murray E, Steinke FH, Rand WM, Young VR. Nitrogen balance response in young men given one of two isolated soy proteins or milk proteins.  J Nutr. 1983 Dec;113(12):2492-7.

4.  Wayler A, Queiroz E, Scrimshaw NS, Steinke FH, Rand WM, Young VR. Nitrogen balance studies in young men to assess the protein quality of an isolated soy protein in relation to meat proteins.  J Nutr. 1983 Dec;113(12):2485-91.

5.  Young VR, Puig M, Queiroz E, Scrimshaw NS, Rand WM.  Evaluation of the protein quality of an isolated soy protein in young men: relative nitrogen requirements and effect of methionine supplementation. Am J Clin Nutr. 1984 Jan;39(1):16-24.

6.  Beer WH, Murray E, Oh SH, Pedersen HE, Wolfe RR, Young VR. A long-term metabolic study to assess the nutritional value of and immunological tolerance to two soy-protein concentrates in adult humans.  Am J Clin Nutr. 1989 Nov;50(5):997-1007

7.  FAO/WHO (1991). Protein Quality Evaluation; FAO Food and Nutrition Paper 51,Rome,Italy.

8.  WHO/FAO/UNU.  Technical Report Series 935.  Protein and Amino Acid Requirements in Human Nutrition. 2007.

9.  IOM. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). 2005.

10.  Sarwar, G. The protein digestibility-corrected amino acid score method overestimates quality of proteins containing antinutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. J. Nutr. 1997, 127, 758–764.

11.  Hughes GJ, Ryan DJ, Mukherjea R, Schasteen CS. Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: criteria for evaluation.  J Agric Food Chem. 59(23):  12707-12712.

12.  Erdman JW Jr, Fordyce EJ. Soy products and the human diet.  Am J Clin Nutr. 1989 May;49(5):725-37.

13.  Friedman M,BrandonDL. Nutritional and health benefits of soy proteins.  J Agric Food Chem. 2001 Mar;49(3):1069-86.

14.  Jeejeebhoy KN. Vegetable proteins: are they nutritionally equivalent to animal protein.  Eur J Gastroenterol Hepatol. 2000 Jan;12(1):1-2.

Chapter 2- Eat a wide variety of nutritious foods

Unequivocal data generated during the past 25 years have shown that soy foods provide nutritionally complete protein based on the soybean’s indispensable amino acid spectrum.  Soy protein is the only widely available high quality complete vegetable protein shown to maintain nitrogen balance when fed as the sole protein source at minimum recommended intake levels1-6. The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) Joint Expert Consultation’s Protein Quality Evaluation Report7 recommended the protein digestibility-corrected amino acid score (PDCAAS), which is a scientific and rational procedure for assessing protein quality.  The protein digestibility-corrected amino acid score (PDCAAS) of isolated soy protein and soy protein concentrate achieves the maximum value of 1.00 and meets all published estimates for the essential amino acid requirements of children and adults8-11.

Soy foods are particularly important because they:

  • provide high quality protein that is comparable to animal proteins, yet more sustainable;
  • are typically low in saturated fat and cholesterol-free; and
  • can be a good source of fiber
  • can be easily incorporated into the diet, as well as serve as a nutritious substitute for foods higher in saturated fat and cholesterol

Soy foods are consistent with the dietary patterns recommended by the Guidelines and are represented in three of the five food categories.  While the 2012 Australian Dietary Guidelines list “170 g tofu” as a suitable food option from the “Lean meat and poultry, fish, eggs, nuts and seeds, and legumes/beans” group, there should also be specific mention of other soy foods in Table 1 of the Australian Guide to Healthy Eating:

1.  Add “soybeans” to the food group “Vegetables and legumes/ beans” recommendation for “75g (1/2 cup) cooked dried or canned beans, chickpeas or lentils, no added salt”

“75g (1/2 cup) cooked dried or canned beans, soybeans, chickpeas or lentils, no added salt”

2.  Add “calcium fortified soymilk” to the food group “Milk, yoghurt, cheese and/or alternatives”.  Currently there is no specific example of “alternative” in this category.  Calcium fortified soymilk represents a nutritionally comparable alternative to cow’s milk.

250 mL (1 cup) calcium fortified soymilk

Soy foods are suitable for vegetarians and those wishing to reduce meat and milk consumption, as they can be a primary source of protein in the diet due to soy’s ability, as a high-quality protein, to promote normal growth, development and heart health in children and adults. 

The overall systematic review and subsequent scoring of scientific literature collected since 2002 to show support for the Dietary Guidelines for Australians appears to be limited. In particular, the review of the literature assessing the benefits of legumes (specifically soy foods and soy protein) for cholesterol lowering included only one meta-analysis of randomized, controlled studies and one randomized controlled trial. In the period from 2002 to 2009 (which was the upper limit of the search conducted by the NHMRC), seven additional meta-analyses15-21 of randomized controlled studies were published and have consistently demonstrated a beneficial effect of soy protein to lower cholesterol.  Three of these meta-analyses15,18,20 are cited in the NHMRC systematic review; however, it was argued that most of the studies evaluated in these 3 meta-analyses used “isoflavone-rich soy protein isolates rather than food”.  It is unclear what rationale was used by the reviewers to conclude that soy protein isolates which contain naturally occurring (not added) levels of isoflavones derived from soybeans are not “food”.  As per Part 1 of the Food Standards Australia New Zealand Act 1991, the legal definition of "food" reads:

5.  Meaning of food:

(1) Food includes: (a) any substance or thing of a kind used, capable of being used, or represented as being for use, for human consumption (whether it is live, raw, prepared or partly prepared); and (b) any substance or thing of a kind used, capable of being used, or represented as being for use, as an ingredient or additive in a substance or thing referred to in paragraph (a); and (c) any substance used in preparing a substance or thing referred to in paragraph (a); and (d) chewing gum or an ingredient or additive in chewing gum, or any substance used in preparing chewing gum; and (e) any substance or thing declared to be a food under a declaration in force under section 6. (It does not matter whether the substance, thing or chewing gum is in a condition fit for human consumption.) (2) However, food does not include a therapeutic good within the meaning of the Therapeutic Goods Act 1989. (3) To avoid doubt, food may include live animals and plants.

Therefore, the meta-analyses of Weggemans15, Taku20 and Zhan18, as well as four additional meta-analyses16,17,19,21 published between 2002-2009, that assessed lipid-lowering effects of soy protein from various soy foods, including soy protein isolates, should be added to the evidence for an effect of legume consumption on the risk of hypercholesterolemia.  Products derived from soybeans are foods consumed by the population, much like products derived from dairy are considered in the dairy foods category. Based on this evidence about soy products, the Grade of “C” assigned to the statement “Does a particular intake of legumes affect the risk of hypercholesterolemia?” is not appropriate and should receive at least a “B” grade to be consistent with the level of evidence for risk reduction afforded by other foods.  For instance, in the systematic review, section 5.3 “Does a particular intake of dairy affect the risk of cardiovascular disease in adults?” the level of evidence is assigned a Grade of “B” based on only two meta-analyses of cohort studies performed by the same senior author.  Based on the guidelines published in 2000 by the NHMRC  “How to use the evidence: Assessment and application of scientific evidence” cohort studies are considered Level III evidence or in other words, provide less support than that obtained with randomized controlled studies or systematic reviews of such studies (Level I). Therefore, we recommend that the NHMRC reconsider the grading of “B” to the level of evidence for supporting the statement  “Does a particular intake of legumes affect the risk of hypercholesterolemia?” as this would appear to be clearly warranted.

In recognition of the wealth of evidence demonstrating soy protein’s ability to lower LDL-cholesterol, 12 countries have approved a soy protein heart health claim:    

  • United Kingdom
  • Japan
  • United States
  • South Africa
  • Philippines
  • Brazil
  • Indonesia
  • Korea
  • Turkey
  • Malaysia
  • Chile
  • Colombia

As an additional note, the statement in the systematic review that isoflavones are proposed to be the “active and important biological constituent (of soy foods)” is not supported by the literature, as six clinical studies using isolated isoflavones published between 2002-2009 have failed to show any independent cholesterol lowering effect22-27.

References

1.  Zezulka AY, Calloway DH. Nitrogen retention in men fed isolated soybean protein supplemented with L-methionine, D-methionine, N-acetyl-L-methionine, or inorganic sulfate.  J Nutr. 1976 Sep;106(9):1286-91.

2.  Istfan N, Murray E, Janghorbani M, Young VR. An evaluation of the nutritional value of a soy protein concentrate in young adult men using the short-term N-balance method.  J Nutr. 1983 Dec;113(12):2516-23.

3.  Scrimshaw NS, Wayler AH, Murray E, Steinke FH, Rand WM, Young VR. Nitrogen balance response in young men given one of two isolated soy proteins or milk proteins.  J Nutr. 1983 Dec;113(12):2492-7.

4.  Wayler A, Queiroz E, Scrimshaw NS, Steinke FH, Rand WM, Young VR. Nitrogen balance studies in young men to assess the protein quality of an isolated soy protein in relation to meat proteins.  J Nutr. 1983 Dec;113(12):2485-91.

5.  Young VR, Puig M, Queiroz E, Scrimshaw NS, Rand WM.  Evaluation of the protein quality of an isolated soy protein in young men: relative nitrogen requirements and effect of methionine supplementation. Am J Clin Nutr. 1984 Jan;39(1):16-24.

6.  Beer WH, Murray E, Oh SH, Pedersen HE, Wolfe RR, Young VR. A long-term metabolic study to assess the nutritional value of and immunological tolerance to two soy-protein concentrates in adult humans.  Am J Clin Nutr. 1989 Nov;50(5):997-1007

7.  FAO/WHO (1991). Protein Quality Evaluation; FAO Food and Nutrition Paper 51,Rome,Italy.

8.  WHO/FAO/UNU.  Technical Report Series 935.  Protein and Amino Acid Requirements in Human Nutrition. 2007.

9.  IOM. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). 2005.

10.  Sarwar, G. The protein digestibility-corrected amino acid score method overestimates quality of proteins containing antinutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. J. Nutr. 1997, 127, 758–764.

11.  Hughes GJ, Ryan DJ, Mukherjea R, Schasteen CS. Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: criteria for evaluation.  J Agric Food Chem. 59(23):  12707-12712.

12.  Erdman JW Jr, Fordyce EJ. Soy products and the human diet.  Am J Clin Nutr. 1989 May;49(5):725-37.

13.  Friedman M,BrandonDL. Nutritional and health benefits of soy proteins.  J Agric Food Chem. 2001 Mar;49(3):1069-86.

14.  Jeejeebhoy KN. Vegetable proteins: are they nutritionally equivalent to animal protein.  Eur J Gastroenterol Hepatol. 2000 Jan;12(1):1-2.

15.  Weggemans RM, Trautwein EA. Relation between soy-associated isoflavones and LDL and HDL cholesterol concentrations in humans: a meta-analysis.  Eur J Clin Nutr. 2003 57(8): 940-6.

16.  Zhou JR. Soy and the prevention of lifestyle-related diseases.  Clin Exp Pharmacol Physiol. 2004 31(Suppl 2): S14-9.

17.  Balk E, et al. Effects of soy on health outcomes.  Evid Rep Technol Assess (Summ). 2005 126: 1-8.

18.  Zhan S, Ho SC. Meta-analysis of the effects of soy protein containing isoflavones on the lipid profile.  Am J Clin Nutr. 2005 81(2): 397-408.

19.  Reynolds K, et al. A meta-analysis of the effect of soy protein supplementation on serum lipids.  Am J Cardiol. 2006 98(5): 633-40.

20.  Taku K, et al. Soy isoflavones lower serum total and LDL cholesterol in humans: a meta-analysis of 11 randomized controlled trials.  Am J Clin Nutr. 2007 85(4): 1148-56.

21.  Hooper L, et al. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials.  Am J Clin Nutr. 2008 88(1): 38-50.

22.  Atteritano M, et al. Effects of the phytoestrogen genistein on some predictors of cardiovascular risk in osteopenic, postmenopausal women: a two-year randomized, double-blind, placebo-controlled study.  J Clin Endocrinol Metab. 2007 92(8): 3068-75.

23.  Aubertin-Leheudre M. Six months of isoflavone supplement increases fat-free mass in obese-sarcopenic postmenopausal women: a randomized double-blind controlled trial.  Eur J Clin Nutr. 2007 61(12): 1442-4.

24.  Ho SC, et al. Effects of soy isoflavone supplementation on cognitive function in Chinese postmenopausal women: a double-blind, randomized, controlled trial.  Menopause. 2007 14(3 Pt 1): 489-99.

25.  Nestel P, et al. An isoflavone metabolite reduces arterial stiffness and blood pressure in overweight men and postmenopausal women.  Atherosclerosis. 2007 192(1): 184-9.

26.  Rios DR, et al. Lack of effects of isoflavones on the lipid profile of Brazilian postmenopausal women.  Nutrition. 2008 24(11-12): 1153-8.

27.  Taku K, et al. Effects of extracted soy isoflavones alone on blood total and LDL cholesterol: Meta-analysis of randomized controlled trials.  Ther Clin Risk Manag. 2008 4(5): 1097-103.

Chapter 3- Limit intake of foods and drinks containing saturated and trans fats, added salt, added sugars and alcohol

Unequivocal data generated during the past 25 years have shown that soy foods provide nutritionally complete protein based on the soybean’s indispensable amino acid spectrum.  Soy protein is the only widely available high quality complete vegetable protein shown to maintain nitrogen balance when fed as the sole protein source at minimum recommended intake levels1-6. The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) Joint Expert Consultation’s Protein Quality Evaluation Report7 recommended the protein digestibility-corrected amino acid score (PDCAAS), which is a scientific and rational procedure for assessing protein quality.  The protein digestibility-corrected amino acid score (PDCAAS) of isolated soy protein and soy protein concentrate achieves the maximum value of 1.00 and meets all published estimates for the essential amino acid requirements of children and adults8-11.

Soy foods are particularly important because they:

  • provide high quality protein that is comparable to animal proteins, yet more sustainable;
  • are typically low in saturated fat and cholesterol-free therefore when soy protein is consumed to displace animal protein which contain higher levels of saturated fat and cholesterol, an “extrinsic” cholesterol lowering effect is consequently attributed to soyfoods12; and
  • soy protein has an “intrinsic” property to lower serum cholesterol12
  • can be a good source of fiber
  • can be easily incorporated into the diet, as well as serve as a nutritious substitute for foods higher in saturated fat and cholesterol

References

1.  Zezulka AY, Calloway DH. Nitrogen retention in men fed isolated soybean protein supplemented with L-methionine, D-methionine, N-acetyl-L-methionine, or inorganic sulfate.  J Nutr. 1976 Sep;106(9):1286-91.

2.  Istfan N, Murray E, Janghorbani M, Young VR. An evaluation of the nutritional value of a soy protein concentrate in young adult men using the short-term N-balance method.  J Nutr. 1983 Dec;113(12):2516-23.

3.  Scrimshaw NS, Wayler AH, Murray E, Steinke FH, Rand WM, Young VR. Nitrogen balance response in young men given one of two isolated soy proteins or milk proteins.  J Nutr. 1983 Dec;113(12):2492-7.

4.  Wayler A, Queiroz E, Scrimshaw NS, Steinke FH, Rand WM, Young VR. Nitrogen balance studies in young men to assess the protein quality of an isolated soy protein in relation to meat proteins.  J Nutr. 1983 Dec;113(12):2485-91.

5.  Young VR, Puig M, Queiroz E, Scrimshaw NS, Rand WM.  Evaluation of the protein quality of an isolated soy protein in young men: relative nitrogen requirements and effect of methionine supplementation. Am J Clin Nutr. 1984 Jan;39(1):16-24.

6.  Beer WH, Murray E, Oh SH, Pedersen HE, Wolfe RR, Young VR. A long-term metabolic study to assess the nutritional value of and immunological tolerance to two soy-protein concentrates in adult humans.  Am J Clin Nutr. 1989 Nov;50(5):997-1007

7.  FAO/WHO (1991). Protein Quality Evaluation; FAO Food and Nutrition Paper 51,Rome,Italy.

8.  WHO/FAO/UNU.  Technical Report Series 935.  Protein and Amino Acid Requirements in Human Nutrition. 2007.

9.  IOM. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). 2005.

10.  Sarwar, G. The protein digestibility-corrected amino acid score method overestimates quality of proteins containing antinutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. J. Nutr. 1997, 127, 758–764.

11.  Hughes GJ, Ryan DJ, Mukherjea R, Schasteen CS. Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: criteria for evaluation.  J Agric Food Chem. 59(23):  12707-12712.

12.  Jenkins DJA, Mirrahimi A, Srichaikul K, Berryman CE, Wang L, Carleton A, et al. Soy protein reduces serum cholesterol by both intrinsic and food displacement mechanisms. The Journal of nutrition 2010;140(12):2302S-2311S.

Page reviewed: 3 January, 2013