Why Should We Eat Offal?
By Jaime Ooi
Table of Contents
For years, the idea of a “healthy diet” revolved around the consumption of a higher proportion of vegetables and grains. This is to ensure we satisfy our body’s needs of essential nutrients and energy; therefore, it can be inferred that we eat for the main reasons of:
but more recently…
- Taste and pleasure
The human body is unable to produce everything required to function; therefore, food consumption is essential to obtain essential nutrients and energy. While the focus has been on the micronutrient content of fruits and vegetables, compared to animal sources, there is a stark difference in nutrient density and bioavailability.
Essential Nutrients and Superfoods
The three main macronutrients are protein, carbohydrates and fat. Humans require external sources of amino (histidine, isoleucine, leucine, phenylalanine, threonine, tryptophane and valine) and fatty acids (Omega-3s and 6s), while there are no existing essential carbohydrates. Evidence suggests that carbohydrates are not a necessity since the body is able to produce its own through a process called gluconeogenesis. The idea here isn’t to bash on carbohydrates but rather offer a more nuanced perspective on the notion that there are essential amino and fatty acids required for optimal bodily function but not derivatives of carbohydrates.
The body is also unable to produce vitamins and minerals; therefore, sufficient amounts are considered as part of a “healthy” diet. Kale, acai berries and turmeric have sparked consumer interest due to their high-nutrient and antioxidant content. However, plant antioxidants and nutrients are mostly bio-unavailable and can cause negative impacts on the digestive process due to the inhibitory effects on enzymes by naturally occurring polyphenols, which interfere with the absorption of amino and fatty acids. (1) A systematic review and meta-analysis of randomized controlled trials on the effects of turmeric and its anti-inflammatory properties found no decrease in inflammatory markers in patients with chronic inflammation (even when black pepper was added, to “enhance” to “activate” anti-inflammatory properties), despite what is promoted and sold in supermarkets. (2)
Comparing Beef Liver and Kale
Nutrients per 100g
Beef Liver (% DV)
Kale (% DV)
|Energy (kcal)||135 (7)||33.5 (2)|
|Total Fat (g)||3.6 (6)||0.5 (1)|
|Protein (g)||20.4 (41)||2.2 (4)|
|Carbohydrates (g)||3.9 (1)||6.7 (2)|
|Calcium (mg)||5 (0.38)||254 (20)|
|Phosphorous (mg)||387 (31)||55 (8)|
|Potassium (mg)||313 (6.7)||348 (7)|
|Iron (mg)||4.9 (27.2)||1.6 (9)|
|Zinc (mg)||4 (36.4)||0.4 (4)|
|Vitamin A/ Retinol (IU)||4,968 (552)||–|
|Vitamin D (IU)||49 (9.8)||–|
|Vitamin E (mg)||0.4 (2.7)||0.7 (3)|
|Vitamin C (mg)||25 (26.9)||93.4 (104)|
|Vitamin B3/ Niacin (mg)||13.2 (82.5)||1.2 (7)|
|Vitamin B6 (mg)||1.1 (64.7)||0.1 (11)|
|Vitamin B9/ Folate (mcg)||290 (72.5)||62 (15.5)|
|Vitamin B12/ Cobalamin (mg)||59.3 (2,471)||–|
Values are based off the latest values from the U.S. Department of Agriculture (USDA) per 100g. % DV, percentage of the Daily Value for each nutrient in a serving of food that contributes to a daily diet based on a 2,000-kcal diet. Mg, milligrams; mcg, micrograms; IU, International Unit.
Compared to kale, beef liver and offal provide a high concentration of bioavailable Vitamin A (retinol compared to beta-carotene found in plants). Liver fell out of consumer interest when saturated fat and cholesterol were demonized despite their high nutrient density.
Vitamin A is important for immune, eye and liver function. A 100g serving of beef liver contains 552% of the recommended daily intake and is one of the only food sources that contain large amounts of naturally occurring vitamin A, making it a viable source of this essential vitamin. A lack of vitamin A is known to cause skin issues (such as acne and psoriasis) and night blindness. A study found that lower Vitamin A intake in Australia since 1995 was related to changes in retinol intake rather than carotenoid, and due to the lower consumption of foods such as organ meats. (3)
B vitamins such as B12 (cobalamin) are essentially non-existent in most plant-based food products, where vegans and vegetarians are susceptible to deficiency by up to 90%. (4) It plays a role in the production of red-blood cells, DNA, and assists with proper neuronal functioning. One serving of beef liver contains:
- Niacin (B3)- 82.5% of the Recommended Dietary Intake (RDI)
- Folate (B9)- 72.5% of the RDI
- Cobalamin (B12)- 2,471% of the RDI
The high vitamin B concentration makes liver’s anti-fatigue factor a favorite supplement amongst bodybuilders in the 60s and 70s, where it was consumed as liver tablets. Similarly, a study on rats found that those supplemented with powdered liver swam for up to 2 hours compared to the other two vitamin and B-complex supplemented groups that only averaged 13.3 minutes. (5)
Although vitamin C is predominantly higher in plant sources, the glucose-ascorbate antagonism (GAA) theory proposes that vitamin C absorption is determined by glucose concentration in the blood stream. Because of their similar molecule structure and absorption pathways, the entry of vitamin C into cells is hindered when glucose is also present; however, the exact amount of each nutrient that promotes or hinders absorption is currently unknown and further investigation is required. (6)
Nutrients in Offal Varieties
Nutrients per 100g
Total Fat (g)
Vitamin A/ Retinol (IU)
Vitamin D (IU)
Vitamin E (mg)
Vitamin C (mg)
Vitamin B3/ Niacin (mg)
Vitamin B6 (mg)
Vitamin B9/ Folate (mcg)
Vitamin B12/ Cobalamin (mg)
Values are based off the latest values from the U.S. Department of Agriculture (USDA) per 100g. % DV, percentage of the Daily Value for each nutrient in a serving of food that contributes to a daily diet based on a 2,000-kcal diet. DV, Daily Value; Mg, milligrams; mcg, micrograms; IU, International Unit.
Apart from liver, other offal varieties also offer a range of nutrients:
- Beef sweetbreads, lungs and spleen contain more than 60% of recommended vitamin C intake, and due to the lack of carbohydrates present, the absorption of glucose would be greater according to the GAA theory. (6)
- Beef spleen contains a high amount of iron, which is essential for oxygen transport and female health.
- Kidney is one of the few products with selenium in a free form (240 µg per 100g, not shown in the table), that assists thyroid functioning.
- Heart contains Coenzyme Q10 (CoQ10), which support the energy demands of high functioning organs within the body such as the heart, kidneys, lungs and liver.
- Bone broth is made by slow cooking marrow bones and connective tissue of animals. This releases a range of essential vitamins and minerals such as calcium, magnesium, potassium, Vitamin A, Vitamin K2, Zinc, omega-3 and 6 fatty acids. It is also high in protein collagen which is essential for skin, hair and nail health. Bone broth is also known to assist in healing “leaky gut syndrome”, due to its high glutamine and gelatin content that maintains the function of the intestinal wall.
Overall, from a nutrition perspective, offal contains a wide range of essential nutrients that contribute to maintaining health and increasing overall energy. Liver is considered the king of organ meats due to its high nutrient content and density; however, contributions of other offal varieties should not be dismissed as they are able to contribute to a varied diet.
Recently, the concept of ‘nose-to-tail’ eating is making a comeback in the media. Offal consumption was featured in articles by the Sydney Morning Herald, ABC News and New York Times magazine that provide the reader with insight on old-school dishes and what to expect from these more nuanced cuts.
Similarly, Michelin stars from Heston Blumenthal to Mario Batali have been featuring organ meats in their fine dining menus.
- Cirkovic Velickovic TD, Stanic-Vucinic DJ. The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties. Compr Rev Food Sci Food Saf [Internet]. 2018 Jan 1 [cited 2020 Oct 28];17(1):82–103. Available from: http://doi.wiley.com/10.1111/1541-4337.12320
- White CM, Pasupuleti V, Roman YM, Li Y, Hernandez A V. Oral turmeric/curcumin effects on inflammatory markers in chronic inflammatory diseases: A systematic review and meta-analysis of randomized controlled trials. Vol. 146, Pharmacological Research. Academic Press; 2019. p. 104280.
- Messina AE, Hambridge TL, Mackerras DEM. Change in Australian Vitamin A Intakes over Time. Curr Dev Nutr [Internet]. 2019 Sep 1 [cited 2020 Oct 30];3(9). Available from: https://pubmed.ncbi.nlm.nih.gov/31598580/
- Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B12 deficiency among vegetarians? Nutrition Reviews. 2013.
- Ershoff BH. Beneficial Effect of Liver Feeding on Swimming Capacity of Rats in Gold Water. Proc Soc Exp Biol Med. 1951;
- Clemens Z. Vitamin C and Disease: Insights from the Evolutionary Perspective. J Evol Heal. 2013;
I am a graduated nutritionist (Bachelor of Food and Nutrition Science, Honours) who is interested in all things to do with how to live a healthy and fulfilling lifestyle.
Although fats were given a bad rep in the past, research has revealed the impact fat has on increasing satiety hormones within the body through various mechanisms. This sparked my curiosity, so during my Honours year, I assessed the heritability and influence of fats on satiety.
Similarly, my interest also lies in the impacts of regenerative farming and nose-to-tail cooking. I’ve had experience curating menu’s in the past, so working with food is something I’ve always loved doing since I was 15. Similar to many people, I’ve dabbled with various ways of eating to find what works for me. It wasn’t until I started increasing my intake of red meat and incorporating liver into my diet that I started feeling stronger, more energized, and alert.
Food and nutrition plays an important role in how we feel, so it makes sense that more research is assessing the impacts of eating in a way that is congruent with how we ate during most of human evolutionary history, and I find this very exciting.