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Want to adopt a Vegan Diet?

Before changing over to a vegan diet, here are a few important facts you need to know to optimise your nutrient intake.

The European Heart Journal has just released interesting results of studies comparing vegetarian and vegan diets.  Just eating plant based foods does not equate to healthy, especially when highly processed foods are included.  Perhaps one of the worst offenders here is fake ‘meat’ made from genetically modified, highly sprayed soy.

Read the full article – Tian Wang and others, Vegetarian and vegan diets: benefits and drawbacks, European Heart Journal, 2023;, ehad436, Published 14 July 2023

The number of people deciding to follow plant-based diets is on the rise around the world, so it is essential to be aware of the most nutrient-dense food options.

A vegan diet is rich in dietary fibre, polyphenols and antioxidants but there are some nutrients that aren’t covered, including vitamins B12 and D, iron, taurine, and omega-3.1 Pathology testing, followed by supplementation if a deficiency is identified is recommended for these nutrients.

A recent clinical study explored the protein density and bioavailability of animal versus plant-based proteins. Fifty-six participants were randomly assigned to seven groups consuming either animal or plant-based protein, gram for gram. Researchers concluded that animal proteins are more digestible and have a higher branched chain and essential amino acid profile (P<0.001) than plant-based proteins, and they are not metabolically equivalent gram for gram. However, interestingly tofu’s amino acid anabolic activity was similar to eggs and pork.2  

Higher amounts of plant-based foods are required to meet daily protein requirements compared to animal protein and this naturally comes with more calories. For example, the number of mixed nuts needed to achieve the same amount of essential amino acids in two eggs delivers 525kcal versus 155 kcal. Tofu and kidney beans had the best amino acid profile of the plant-based foods in the study, while mixed nuts and peanut butter had the lowest.2

Antinutrients such as lectins, glutens, phytates and oxalates in plant-based foods may contribute to gastrointestinal inflammation and intestinal permeability, compromising the absorption of essential nutrients.3 Cooking can help reduce these plant chemicals, while fermenting can also lessen lectins in certain foods such as kombucha, pickles and sauerkraut.

This easy-to-follow table highlights common nutrient deficiencies encountered on a vegan diet, and importantly, shows how to identify deficiencies using pathology testing.

Common Nutrient Deficiencies to be Mindful of Essential for Deficiency Symptoms Daily Dosing


Pathology testing4 (vary from laboratory-to-laboratory)
 Protein  Amino acids needed for building and repairing the body, immune support, growth, bone building. Stunting, physical weakness, oedema, vascular dysfunction, impaired immunity.5  1.0 – 1.6g/kg bodyweight5  Albumin: Made from dietary protein, low levels indicate protein deficiency or malabsorption issues. Albumin below 28 may be problematic. Ideal albumin should be around 35 – 45. 
Iron Haemoglobin synthesis, oxygen transport, a cofactor for serotonin, dopamine, and norepinephrine synthesis, electron transfer, energy production, hair and nail growth, bone homeostasis, DNA repair. Fatigue/lethargy, anaemia, cognitive impairment, developmental delay, amenorrhoea, hair loss, enlarged liver  Supplement dosing: 24mg

Upper level of intake from all sources = 45mg/day6

Clinical note:
1. Doses of more than 30mg orally may trigger mucosal blocking of iron to prevent overload.
2. Best to dose in the morning when hepcidin is lowest, increasing absorption capacity.7
3. Ferritin levels usually increase in men after 50 and women after menopause. Inflammation can elevate ferritin levels. 


Serum iron:
10-30 umol/L   TIBC:
45-70 umol/L

Transferrin saturation:

>30-200 ug/L in menstruating females. 8
>30-300 ug/L In post-menopausal females and males

Reference ranges alter for different life stages, age, gender, and individual health status. 

Vitamin B12  A cofactor for the methylation cycle, red blood cell production, tissue repair, and DNA synthesis. Confusion, memory loss, depression, irritability, fatigue, easy bruising, pernicious & macrocytic anaemias, infertility, peripheral neuropathy, loss of appetite, nausea, glossitis, dermatitis & skin sensitivities. Low B12 can elevate homocysteine levels, increasing the risk of heart attacks and strokes.9  RDI: 2.4mcg.

Insufficient data to allow setting an upper limit, no adverse effects have been associated with excess vitamin B12.6

Pernicious anaemia, gastric bypass, inflammatory bowel disease, malabsorption: 500-1000mcg orally.9

Clinical note:
Limited B12 may be sourced from certain plants exposed to bacteria, however, most is obtained from animal foods.  

Serum B12: 
<150 pmol/LActive B12
(Holotranscobalamin – is now considered the best indicator of B12 status): 23-100 pmol/L10

Methylmalonic acid in blood:
>0.4 mol/mL  

Vitamin D Vital for bone health, maintaining serum calcium and phosphorus levels, enhancing immune function, neuromuscular function, and mental health. Osteoporosis, increased fracture risk, muscle weakness, bone pain, psoriasis, depression, autoimmune disease. 80mcg (3200IU)6

Clinical note:
In the absence of adequate sunlight exposure higher doses of vitamin D may be required.  

Serum 25OHD:
>75 nmol/L 
Omega-3 (EPA/DHA) Component of cell membranes enhancing membrane fluidity, reducing platelet aggregation, stimulation of growth, repair, and reproduction, DNA regulation, modulates inflammation, essential component of the central nervous system. Rough scaly skin, alopecia, eczema and dermatitis, cracked heels, dry hair, brittle nails, stunted growth, learning disorders, depression. Omega-3:
3000mg. Marine sources of omega-3 available from seaweed and algae.Clinical note:
Choose ethically sourced and sustainable fish oils with 3rd party testing for low pesticide, plastics, and heavy metal contaminants.  
Red blood cell and fasting plasma omega-3 (functional testing)11:

Total O3: 4.50-13.40

EPA: 0.10-1.20

DHA: 2.50-7.50 

Cholesterol Essential for cell membrane fluidity, vitamin D synthesis, adrenal and sex hormone synthesis, bile salt and myelin sheath synthesis. Nervous system dysfunction, mood disorders including anxiety and depression12, reduced hormone production and immune function. Total cholesterol:
4-5.5mmol/LHDL: <4.0 mmol/L

LDL: <2.5 mmol/L

Triglycerides: <1.7 mmol/L fasting 

When cholesterol pathology levels are below 4.0 mmol/L, and you are experiencing severe mood changes or hormone disruption, consider adding butter (30.1mg cholesterol per tablespoon) or eggs (212mg cholesterol per egg) to your diet.  Organic and free-range farming is an ethical and sustainable form of farming maintaining high animal health and welfare.  

Source:  BioConcepts

  1. Sakkas H, Bozidis P, Touzios C, et al. Nutritional status and the influence of the vegan diet on the gut microbiota and human health. Med. 2020;56(2):1-15. doi:10.3390/medicina56020088
  2. Park S, Church DD, Schutzler SE, et al. Metabolic Evaluation of the Dietary Guidelines’ Ounce Equivalents of Protein Food Sources in Young Adults: A Randomized Controlled Trial. J Nutr. 2021;151(5):1190-1196. doi:10.1093/jn/nxaa401
  3. Punder K De, Pruimboom L. The Dietary Intake of Wheat and other Cereal Grains and Their Role in Inflammation. Published online 2013:771-787. doi:10.3390/nu5030771
  4. Weatherby, D; Ferguson S. Blood Chemistry and CBC Analysis. 1st ed. Bear Mountain Publishing; 2002.
  5. Wu G. Dietary protein intake and human health. Food Funct. 2016;7(3):1251-1265. doi:10.1039/c5fo01530h
  6. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand: Including Recommended Dietary Intakes.; 2006.…
  7. Shinoda S, Arita A. Regulatory mechanisms of intestinal iron absorption : Iron-deficient mucosal cells respond immediately to dietary iron concentration. 2014;3(4):399-407. doi:10.7600/jpfsm.3.399
  8. Australasia TRC of P of. Interpreting serum ferritin. Common Sense Pathol. 2013;(October):2-8.…
  9. Stabler SP. Vitamin B 12 Deficiency. N Engl J Med. 2013;368(2):149-160. doi:10.1056/NEJMcp1113996
  10. Austin Health Pathology. Holotranscobalmin. Austin Pathology Test Directory. Published 2021. Accessed December 20, 2021.…
  11. Nutripath Integrative Pathology Testing. Omega 3 Index Profile. Published 2016.…
  12. Fiedorowicz J, Haynes W. Cholesterol, mood, and vascular health: Untangling the relationship: Does low cholesterol predispose to depression and suicide, or vice versa? Curr Psychiartry. 2010;9(7):17-A.…
  13. Department of Health and Ageing. Australia Dietary Guidelines. Australian Dietary Guidelines. Published 2013.…