Protein is one of the important nutrients we need everyday for growth, maintenance and repair. Therefore, it is important that we obtain sufficient amount everyday.
What are the functions of protein?
Protein is needed in every part of our body. The hair, muscle, nail, blood, bone, nerve all require protein to form as the structure. Enzyme, antibodies, hormone and hemoglobin are made up of protein. Collagen, the glue like protein, is an important component of tendon, bone, connective tissue and cartilage.
How much protein do we need?
- Normal adult (including elderly) – 0.8 g per kg of body weight per day
- Children (1-3 yrs old) – 16 g per day
- Children (4-6 yrs old) – 24 g per day
- Children (7-10 yrs old) – 28 g per day
- Pregnant mothers – 60 g per day
- Lactating mothers – 62-65 g per day.
Where do you find protein?
The most common source of protein is from meat, dairy, nuts, seeds, beans and whole grains
Amongst all these sources, soy protein is the most complete protein. It contains all the 8 essential amino acids, rich source of iron, calcium, zinc and Vitamin B complex. It is also rich in phytochemicals and has the highest level of isoflavone.
Recently, US FDA ( Food Drug Administration) and WHO ( World Health Organization) adopted the Protein Digestibility Corrected Amino Acid Score (PDCAAS) as the preferred method of determining the protein quality. PDCAAS of 1 is the highest and 0 is the lowest.
- Casein (milk protein) – 1
- Egg white – 1
- Soy protein – 1
- Whey ( milk protein) – 1
- Beef – 0.92
- Soybean – 0.91
- Chickpeas – 0.78
- Fruits – 0.76
- Vegetables – 0.73
- Legumes – 0.70
- Cereal – 0.59
- Whole wheat – 0.49
As you can see from the list above that soy protein is equivalent in the protein quality to milk protein and is even better than beef.
In fact, soy protein has many other benefits:
1) Reduce Cholesterol
Soy protein can reduce blood total cholesterol, LDL and triglycerides. Such benefits can be obtained by consuming 25 g of soy protein a day. That is equivalent to 1-2 cups of soya milk or 1 and ¼ cups of tofu. Even US FDA has approved such health claims.
JW Anderson did a meta analysis of the effect of soy protein on lipid from 38 controlled clinical trials of 730 volunteers. Animal protein was replaced by soy protein and found that cholesterol dropped by 9.3%, LDL reduced by 12.3% and HDL increase by 2.4%
2) Obesity and Diabetes
Studies have found that isoflavone component in the soy protein helps to control blood sugar and insulin resistance. There were also evidence that show that soy protein has a positive influence on increasing fat breakdown and prevent fat synthesis in the liver.
The phytochemicals in soy protein helps to reduce the risk of breast cancer and prostate cancer. One of the phytochemical called Geinstein is known to block cancer development by preventing tumor from creating more blood vessels that provides nourishment for the tumor growth.
The phytoestrogen in soy protein protects women from bone loss and maintain a healthy heart during menopause.
Arjmandi et al reported in the Journal of Clinical Endocrinology & Metabolism in 2003 that soy protein has a positive influence on bone and calcium balance in menopause women. The effect is significant in women who are not receiving hormone replacement therapy.
5) Vegetarian and Vegan
Most vegetarian and vegan are lacking in Vitamin B12 because it is only found in animal product. So, soy protein is an excellent source for Vitamin B complex.
6) Children who are lactose intolerance
Children who are lacking in the enzyme to digest lactose and galactose found in milk will require soy protein as an alternative source.
What are the dangers of soy protein?
There concerns of the isoflavone content in soy protein that may impact the male fertility. Soy being relatively high purine can lead to gout.
A clinical study reported by Mitchell J H in Clinical Science in 2001 on the effect of isoflavone supplement on the semen quality. The conclusion was isoflavone has no effect on the quality of sperm count, sperm volume, sperm motility and morphology.
While soy protein is known to be high in purine content, study has shown that the purine from meat, fish and non purine containing alcohol have a higher risk of gout. Go for soy protein where the skin of the soybean is removed, as it is the skin that contributes to the purine content.
So are you getting enough protein? Share with me in the comment box below.
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