The Journey of Discovery: A Historical Perspective on β-carotene

β-carotene, a pivotal precursor to vitamin A, holds a profound significance in the realm of nutrition and biochemistry. Its narrative unfolds through a series of meticulous experiments and groundbreaking revelations by pioneering scientists, each contributing to our understanding of its properties and role in human health.

The inception of β-carotene's journey dates back to 1831 when Heinrich Wilhelm Ferdinand Wackenroder crystallized it from carrots. Little did he know that his discovery would pave the way for future advancements in nutritional science. Wackenroder's doctoral dissertation on anthelminthics in the vegetable kingdom, published in 1826, foreshadowed his later work and earned him prestigious recognition, setting the stage for his subsequent research endeavors.

In 1847, William Christopher Zeise, a Danish organic chemist, recognized β-carotene's hydrocarbon nature, although his analyses initially yielded a composition of C5H8. It wasn't until 1886 when Léon-Albert Arnaud confirmed its hydrocarbon nature and proposed a formula close to the theoretical composition of C40H56, a milestone achievement acknowledged by the French Academy of Sciences.

The definitive empirical formula of β-carotene, C40H56, was established in 1907 by Willstatter and Mieg, marking a significant leap forward in our comprehension of its chemical composition. However, the true elucidation of its structure awaited the pioneering work of Paul Karrer in 1930-31. Karrer's extraction of vitamin A from cod-liver oil and determination of its composition marked a watershed moment, earning him a Nobel Prize and establishing a foundational framework for future research in the field.

The link between β-carotene and vitamin A remained elusive until 1919 when Steenbock proposed a potential relationship between the two. However, it wasn't until 1965 that Jim Olson and DeWitt Goodman independently demonstrated the formation of retinal, the aldehyde form of vitamin A, from β-carotene in cell-free extracts of liver and intestine. This groundbreaking revelation shed light on the vital pathway of β-carotene metabolism, cementing its status as a crucial precursor to vitamin A and revolutionizing our understanding of its physiological role.

In conclusion, the history of β-carotene is a testament to the relentless pursuit of scientific inquiry and the cumulative efforts of visionary researchers. From its serendipitous discovery in carrots to the elucidation of its chemical structure and metabolic pathways, β-carotene's journey exemplifies the transformative power of scientific discovery in shaping our understanding of nutrition and human health.
The Journey of Discovery: A Historical Perspective on β-carotene

What is carotenemia?

Carotenemia is yellowing of the skin resembling jaundice caused by the excess carotene in the blood, most commonly found on the palms, soles of the feet and central third of the face and in the sweat.

Carotenemia does not lead to coloration of the membranes that line eyes, unlike jaundice. The accumulation of β-carotene is not associated with the toxicity character by excessive vitamin A.

This condition is caused by eating too much of certain vegetables and fruits rich in carotene, or is the result of therapy with β-carotene for certain disorders (such as erythropoietic, protoporphyria).

Women who consumed 12 mg or more of β-carotene daily for over 6 weeks by constant munching on foods such as dried green pepper flakes or carrots or by taking ‘tanning pills’ tend to develop carotenemia.

Skin color and fertility return to normal within 2 to 6 weeks after high level of intake are discontinued.

The linear relationship between β-lipoprotein and β-carotene may cause carotenemia in hyperlipidaemia-associated disorders, such as diabetes mellitus, nephritic syndrome and hypothyroidism.

Liver disease may cause carotenemia due to impaired conversion of β-carotene into vitamin A.

Supplementation with high levels of β-carotene when there is alcohol induced liver damage can lead to toxic symptoms.
What is carotenemia?

Carotene: precursor of vitamin A

The two primary isomers of carotene are:
*α-Carotene
*β-Carotene

β-Carotene is the more common form. β-Carotene (C40H56) is a fat soluble plant pigment found in red, orange and yellow vegetables and fruits.

β-Carotene is converted to vitamin A (retinal, retinol, retinoic acid), when the body is in short supply. It is an antioxidant – a compound that blocks the action of activated oxygen molecules that can damage cells.

Vitamin A is essential for the human body in that it assists the body’s immune system and helps battle eye disease, such as cataracts and night blindness, various skin ailments such as acne, signs of aging, and various forms of cancer.

Commercially, β-Carotene is used as a safe food coloring. β-Carotene is the most plentiful of the orange-yellow plant pigments in foods, and it has the highest vitamin A activity.

Because of differences in uptake, storage and chemical processing, only about one-sixth of the β-Carotene in a plant food ends up as vitamin A (retinol) in the body.
Carotene: precursor of vitamin A