What Is All the Fuss About Soya?

What Is All the Fuss About Soya?

A few weeks ago we challenged you to embark on a more vegetarian / vegan – type diet and lifestyle, with enormous health benefits to you, and a significant impact on protecting our environment.

For starters: why don’t you try this Soy Con Carne vegan recipe (courtesy of Hilda Lategan in her SA recipe book: Versatile Vegetarian Recipes)

Now let’s look at the health benefits of Soya…


SOY PROTEIN is as complete a protein as is found in meat / chicken / fish / dairy / eggs, as it contains the full quota of all the essential amino acids required for human health. There are many formats in which one can consume soya, for example, soya mince and nuggets, soya milk, soya porridge (Soya Life Instant Porridge available in Dischems and some other SA outlets), drinks and meal replacers containing soy protein isolate as its protein source, tofu, miso, tempeh and many more soy foods.

The nutritional value of processed soy protein (isolated soy proteins and soy-protein concentrates) in human protein and amino acid nutrition is evaluated on the basis of a review of studies of growth and nitrogen balance in infants, children, adolescents, and adults.

Findings show that well-processed soy-protein isolates and soy-protein concentrates can serve as the major, or even sole, source of protein intake and that their protein value is essentially equivalent to that of food proteins of animal origin.

Soy proteins have also been found to be of good quality to include in hypocaloric diets for weight reduction in obese subjects. Finally, the data indicate that soy proteins are well-tolerated and of good acceptability.

Unlike most other plant-based protein sources, quinoa and soy products provide all of the essential amino acids.

  • A cup of cooked quinoa: 8 grams of protein
  • 90g serving of tofu: 6 grams of protein
  • A cup of soybeans: 29 grams of protein


Soy Beans are the most nutritious plant food available, consisting of:

  • All 3 of the macro-nutrients required for good nutrition:
    • COMPLETE protein, i.e. contain ALL the essential amino acids in the amounts needed for human health; in an amino acid profile close in quality to meat, milk and egg protein
    • Carbohydrate; and
    • Fat (soy oil is rich in essential fatty acids, phospholipids, natural sterols – all of which have known important health benefits)
  • Vitamins (including folic acid)
  • Minerals (including calcium and iron)
  • Prebiotics (e.g. Raffinose and Stachyose, which “feed” the good colonic bacteria = probiotics, resulting in a stronger, healthier colon with enormous benefits to the immune system).
  • Fibre
  • Isoflavones (accounting for 75% of soy’s protective effects in the human body)

When soya beans are harvested, they are put through a variety of processes to produce various products:

  • SOY OIL is used in the BAKING Industry
  • SOY FLOUR is extensively used in BAKING (e.g. breads), SOY MEAT SUBSTITUTES, SOY DAIRY and BEVERAGES
  • SOY MILK (made from ground soy beans) is used to make SOY DAIRY and BEVERAGES
  • SOYA PROTEIN CONCENTRATES and ISOLATES are widely used in the Food Industry to make protein – enriched products or High Protein foods / beverages


  • Soy Fibre

    • Soybeans are an excellent source of dietary fibre (found in the outer hull):
      • 6g fibre/1 cup cooked soybeans; the extracted hull is often used as a fibre additive for breads, cereal and snacks.
    • Both soluble and insoluble fibre is found in soybeans.
    • Soluble fibre is proven to assist with lowering of blood cholesterol levels, and controlling of blood glucose (sugar) levels.
    • Insoluble fibre increases stool bulk, may prevent colon cancer, and can assist in reducing symptoms of irritable bowel syndrome.
  • Soybean Oil

    • +/- 85% unsaturated (HEALTHY!) fats
    • NO cholesterol
    • Unsaturated fats have been proven to lower blood cholesterol levels
    • Rich in 2 essential fatty acids: linoleic and linolenic acids, which are not produced by the body, yet are essential to human health.
  • New Qualified Health Claim:

20.5g of soybean oil may reduce the risk of Coronary Heart Disease. It must replace Saturated Fat and not increase the total calories.

Whole Soybeans Foods:

  • Full fat flour – made from whole soybeans (has the same protein, fat and fibre content as the whole bean).
  • Soymilk – made from ground soybeans that are mixed with water to form a milk-like liquid. Excellent source protein, B-vitamins and iron. Low levels of saturated fat and no cholesterol.

Traditional Asian Soy Products:

  • Tofu soybean curd
  • Miso thick, high-protein paste made from soybeans, salt and a fermenting agent
  • Natto fermented, cooked whole soybeans
  • Tempeh Whole cooked soybeans infused with a culture to form a chewy cake
  • Soybean sprouts  eaten raw in salads / stir-fry’s; rich in Vitamins A, B and C.
  • Soy sauce high in sodium, rich in flavour: made from whole soybeans, wheat flour, fermenting agents: fermented for about 18months.


Definition of a “Functional Food”:

“A food used to increase / improve health; and contributes to reducing the disease burden”

SOY as a functional food:

COMPLETE PROTEINVegetarians AND Non-vegetarians
LOW GI CARBOHYDRATESPrevent and treat metabolic syndrome, diabetes, heart disease, chronic fatigue
FIBRECardio-protective; colon health
PREBIOTICSColon health
ESSENTIAL FATTY ACIDSBrain and eye health
VITAMINS (B-Co, Selenium)Cardio-and cancer- protective
MINERALS (Iron and Zinc)Oxygen transport, immune-boosting
ISOFLAVONESImproved oestrogen metabolism
  • Soy is low GI – sustaining blood sugar levels
  • Proven benefits in normal health: i.e. PREVENTION of chronic diseases of lifestyle
    • Cardiovascular disease (Curr Pharm Biotechnol: April 2012)
    • Diabetes (Nutrition Reviews 2009)
    • Hypertension (J Hypertens: Feb 2013; Nutr Metab Cardiovasc Dis:June 2012)
    • Certain Cancers (BMC Cancer: May 2013; Anticancer Res: Jan 2013; Epigenomics:Dec 2011)
  • Role in TREATMENT of Lifestyle Diseases
    • Diabetes: Type 1 and Type 2
    • Hypertension
    • Obesity
    • Colon disorders


(Refer to detailed articles on each of these myths written in 2017)

In order to understand the truth about soy as a beneficial rather than harmful food, one needs to understand the biochemistry of soya, especially phytoestrogens, which are responsible for >75% of the beneficial effects of soya in the body. 

Phytoestrogens are plant compounds that can beneficially influence oestrogen synthesis and metabolism through a variety of mechanisms, and are currently being extensively investigated as a potential alternative therapy for a range of conditions associated with oestrogen imbalance (including menopausal symptoms, PMS, endometriosis, prevention of breast and prostate cancer, and protection against cardiovascular disease and osteoporosis).

There are 2 types of phytoestrogens: ISOFLAVONES and LIGNANS.

  1. Isoflavones

Found in Soy (most common food source of isoflavones), legumes, alfalfa, clover, licorice root and kudzu root.

Higher intakes of soy products and isoflavones (as is found in traditional Japanese diets) are associated with low rates of hormone-dependent cancers.    THE AVERAGE DAILY ISOFLAVONE INTAKE OF JAPANESE WOMEN is 20-80mg; WHILE THAT OF AMERICAN WOMEN is 1-3mg.

Soy Isoflavones are antioxidants, and are the active components in the soy bean accounting for +/-          75% of the beneficial effects of soy-based foods in human health.

Soy isoflavones have 3 important functions:

  1. When oestrogen levels are high, isoflavones block the more potent forms of oestrogen produced by the body. In this way they may help to prevent hormone-driven diseases, such as breast and prostate cancer.
  1. When oestrogen levels are low, as they are after menopause, isoflavones substitute for the body’s own oestrogen. Adequate oestrogen can possibly reduce hot flushes; and may also assist in increasing bone mineral density, thus preventing osteoporosis in post-menopausal women.
  1. These isoflavones / plant sterols have proven cholesterol-lowering effects. In this way they assist in the prevention of hyperlipidaemias, and cardiovascular disease.

Typical Soy Myths include: 

  1. Eating soy increases breast cancer risk

Most of the concerns surrounding soy foods have to do with their impact on the many bodily systems influenced by oestrogen. Breast cancer, especially oestrogen receptor-positive breast cancer, is a primary concern.

However epidemiologic studies that followed large populations of healthy women for many years have shown either NO association between soy and breast cancer OR a PROTECTIVE association from eating soy.

Even studies of a combined total of 9000 breast cancer survivors, looking at their eating habits and lifestyle factors after cancer, showed that eating soy actually lowered the risk of breast cancer recurrence, even in women with oestrogen receptor-positive tumors, and regardless of whether they were taking tamoxifen. 

Explanation as to why soy’s phytoestrogens may not be the powerful cancer causers they were once thought to be:

  • While isoflavones may act like oestrogen, they also have anti-oestrogen properties: they block the more potent natural oestrogens from binding to the oestrogen receptor.
  • Isoflavones also stop the formation of oestrogens in fat tissue and stimulate production of a protein that binds oestrogen in the blood, making it less able to bind to the receptor.
  • They also have antioxidant and anti-inflammatory properties and may work in other ways to REDUCE cancer growth. 

Soy foods should be recommended to breast cancer survivors. 

  1. Soy causes feminization in men

Recent studies (9 identified clinical studies) showed that neither isoflavone supplements nor isoflavone-rich soy affects total or free testosterone levels. In addition there is no evidence that isoflavone exposure affects circulating oestrogen exposure in men.

  1. Soy phytoestrogens inhibit thyroid function

After extensive research in this field has been conducted, the final conclusion is that “only very high doses of soy phytoestrogen supplementation MAY induce clinical hypothyroidism in a minority of patients with subclinical hypothyroidism”. 

So, to sum up: use soy foods freely in vegetarian and vegan diets, knowing that:

  • It is a complete protein
  • It is versatile and can be consumed in many ways (soy-based cereals/porridges; soya mince and meat analogues, such as soya patties / strips / cubes and sausages; soya milks; fermented soy products such as tofu)
  • It is safe for all (except those allergic to soya: <0.5% of the population) – including those at risk of oestrogen imbalances (menopause / breast cancer / osteoporosis).
  • It is safe (in fact recommended) for kids and teens.
  • It is cheap!
  • It is easy to prepare. 

Be a healthy vegetarian / semi-vegetarian / vegan:  – incorporate soya in many ways – and as such protect your planet!

Enjoy your SOY!

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