Chazal (Menachos 29b) teach us that the world was created using the mystical attributes of the letters of the Alef Bais. Each letter contributed an essential and unique ingredient to the spirituality of the world, which together completed the creation. Chazal also teach us that there is a symbiotic relationship between the spiritual and physical worlds. When scientists began analyzing the myriad of components in the foods we eat and determined that they contained certain micronutrients that were vital to life, they chose to categorize them by the letters of the alphabet. Vitamins are known by their alphabetical acronyms, and indeed have the ability to affect both our physical well being through their nutritional value and our spiritual well being through the Kashrus issues that they present.

A vitamin is defined as a nutritional substance necessary for life but one that cannot generally be produced by the body itself. The term "vitamine" was coined to stand for vita (life) and amine (a specific family of compounds containing nitrogen, originally thought to be a trait common to all such compounds). When further research showed that some vitamins contained no amine structures, the final -e was dropped, leaving the term vitamin, as we know it today. While vitamins were only identified as specific nutritional factors within the past hundred years, their properties have been known since ancient times. Some 3500 years ago King Amenophis IV in the Old Egypt ate liver to help him see clearly at night, and Hippocrates indeed healed night-blindness with raw liver soaked in honey. While neither understood the chemical basis for this therapy, science has since ascribed the curative properties of liver to a chemical called retinol. Since retinol was the first vitamin to be identified, it was given the name Vitamin A. As other vitamins were discovered, they were identified by subsequent letters of the alphabet. [The "missing letters" in the vitamin alphabet came about because some compounds were originally thought to be vitamins and were given a letter, but subsequent research led to their being excluded from the list.] Vitamins were also grouped by the general biological systems they affect. For this reason, several vitamins are identified as subscripted numbers under the "B" group. [Again, some numbers were assigned and then rescinded, leaving breaks in the sequence.] Most vitamins were originally identified in animal tissue, and were these to have remained the source of our vitamin supplements we might have serious Kashrus concerns. Fortunately, virtually all vitamins today are produced by other means. Kashrus concerns exist nonetheless, and pose some interesting Halachik questions.

Vitamins are divided into two categories - fat-soluble and water-soluble varieties. Vitamin A is a fat-soluble vitamin, and in nature can only be found in fatty animal tissue. Many fresh vegetables, especially orange and yellow ones (e.g. carrots), contain beta‑carotene, which is a precursor to Vitamin A and is easily converted by the human body from its inactive form in the vegetables to the active form. Historically, however, fresh vegetables were only available seasonally, and for hundreds of years children looked forward to a regimen of cod liver oil that provided them with this nutrient, as well as Vitamin D. Today, we obtain our Vitamin A from a number of sources such as butterfat, where it is also plentiful, as well as through eating fresh vegetables. With the advent of butter replacements such as vegetable margarine, and in our current zeal to reduce the butterfat content of the dairy foods we eat, there was a concern that an insufficient amount of Vitamin A would be available in our diet. The government has therefore mandated that Vitamin A be added to low-fat dairy products and beta-carotene to margarine (where it is also used to provide color). While the original sources of Vitamin A were of non-Kosher animal and fish origin, modern Vitamin A, used in the forms of palmitate and acetate, are produced synthetically and poses little inherent Kashrus concern. However, palmitic acid (used to produce the palmitate ester that is most bio-available, i.e. the easiest for humans to use) and other oils used to store them do require a Hashgacha. Products that advertise natural Vitamin A, sometimes referred to as -Retinol, generally come from animal tissue and must, therefore, have a reliable Hechsher.

Vitamin D is another fat-soluble vitamin, and was identified as necessary to prevent rickets and other diseases affecting bones. Vitamin D is called the "sunshine vitamin", because it is produced in the body by the reaction of solar UV irradiation with cholesterol. This reaction occurs just under the skin. However, many people do not get enough sunlight, and Vitamin D is now routinely added to milk to ensure an adequate amount together with the calcium in the milk. The Halachik issues relating to Vitamin D, however, are quite interesting. Two commercially available forms of this vitamin are available, Vitamin D­­­₂ and Vitamin D₃. Vitamin D­­­₂ is produced by irradiating a chemical called ergosterol, converting it to ergocalciferol (Vitamin D­­­₂). Ergosterol is produced by a fungus, so named because it was first isolated from a fungus growing on rye (ergot). Today, a strain of yeast that produces a far higher yield of ergosterol is grown in large fermentors and although it requires a Kosher certification, as do all fermentation products, it poses no innate Kashrus concern. Passover certification would depend on the Passover status of the yeast.

Vitamin D₃ is produced by irradiating 7-dehydrocholesterol, a product derived from the cholesterol found in the skin, which is thereby converted into cholecalciferol (Vitamin D₃). It is the source for this cholesterol that poses the potential Kashrus concern. Sheep's wool has been used as a clothing material since the dawn of time (see Sota 11a, where according to one opinion the clothing supplied to Adam and Chava was wool). While on the sheep, however, wool is dirty and oily, and wool processors wash raw wool with various chemicals to remove this grease. From this washing process hey obtain wool grease, which is processed into a lubricant called lanolin. When lanolin is further processed and irradiated it is converted into Vitamin D₃. The question is whether lanolin itself is Kosher, since it is an excretion from a live animal. For many years, some authorities recommended avoided using Vitamin D₃ under the mistaken belief that the lanolin was somehow animal fat that was exuded from the flesh into the wool, a misunderstanding of the term wool "fat". Were this to be the case, it would have been forbidden as Basar Min Hachai (flesh from a living animal). Upon further clarification, however, it was determined that lanolin was actually a secretion of the skin, and this concern became moot. Its status as a secretion of a living animal, however, does leave room for discussion. It may be argued that it is still subject to the rule of Yoze, something that is produced by a forbidden animal (in this case, one that is not properly slaughtered) remains prohibited. Much has been written on this point, with Halachik authorities arguing on both sides. Some have argued that since, during processing, the lanolin becomes inedible it is no longer a subject of concern since the prohibition is only one of Yoze and not an inherent prohibition. In addition, some have argued more to the point - that wool is a permitted item per se and items derived from it pose no Halachik concern. On the other hand, some have argued that lanolin should be treated as any other prohibited excretion, and they thus avoid using Vitamin D₃.

Vitamin E, another fat-soluble vitamin, poses a totally different Kashrus concern. Vitamin E was originally identified in wheat germ oil and was named tocopherol (from the Greek "to bring forth child") because it was deemed essential to reproduction. Its primary form, α-tocopherol, can be produced synthetically and poses little Kashrus concern. Natural Vitamin E, known as mixed tocopherols, is currently produced from a by-product of the soybean oil industry. Crude vegetable oil contains many impurities, which must be removed to produce the edible oil we use in cooking. As part of the oil refining procedure the oil is deodorized, a process by which the volatile impurities are distilled from the oil and removed as a vapor. This deodorizer distillate is rich in mixed tocopherols, and is condensed and processed into natural Vitamin E. The Kashrus concern stems from the fact that many edible oil plants refine both vegetable and animal fats. In such a case, soy deodorizer distillate from a deodorizer that is also used for animal fat deodorizing would be non‑Kosher. Today, literally hundreds of soybean oil refineries around the world are monitored by Kashrus organizations to ensure that a formerly discarded material indeed meets Kosher requirements.

Vitamin K is somewhat unique in that it exists in both oil and water-soluble forms. Vitamin K is essential to the proper clotting of blood, and received its alphabetic designation from the German word "koagulation". Vitamin K₁ (phylloquinone) was originally isolated from alfalfa sprouts, and can be found in many green vegetables such as cabbage, spinach, and turnip greens. Vitamin K₂ (menaquinone) is produced by bacteria that are normally resident in a person's intestines. A synthetic version, Vitamin K₃ (menadione), is the form generally used as a vitamin supplement, and poses no Kashrus concerns.

All fat-soluble vitamins, however, do share one major Kashrus concern. In their natural state fat-soluble vitamins are dissolved in an oil emulsion, but in order to produce a vitamin tablet they must be converted into a powdered form. This is accomplished through a process called spray drying, whereby a fine mist of the vitamin in the oil emulsion is sprayed into hot air. The subsequent drying process creates a powder. However, when exposed to air these vitamins tend to oxidize and become rancid, and gelatin is often used to counteract this problem through a process called microencapsulation. Gelatin is added to the vitamin emulsion in order to form a protective coating around each particle as the powder is formed. While other protective agents (such as gum of acacia) are used, gelatin is the most effective and its use - at up to 45% of the finished powder - creates a Kashrus concern with otherwise inherently Kosher vitamins. To resolve this issue, some vitamin companies use Kosher fish gelatin to ensure acceptability to the Kosher consumer.

The B Vitamins, as well as Vitamin C, are water-soluble, and are produced through a variety of synthetic and fermentation processes. Vitamin C, or ascorbic acid, was first recognized as an important nutrient by the surgeon general of the British Royal Navy, when he prescribed fresh lemons on ocean voyages to combat scurvy amongst the sailors (engendering the nickname for British sailors as limies). While Vitamin C is indeed found in abundance in many fruits and vegetables, the modern production of Vitamin C relies on the fermentation of sorbitol (a carbohydrate) and subsequent chemical treatments to convert it into ascorbic acid. In addition to its value in nutrition, ascorbic acid serves to prevent oxidation in processed fruits and is routinely added for that purpose. The Kashrus concern for this material primarily involves Passover. Sorbitol is produced from glucose, which in turn is produced by the hydrolysis of various starches. While cornstarch is used to produce glucose in North America, in many other parts of the world wheat starch is used. Glucose (and sorbitol) produced from wheat starch is Chometz and may not be used on Pesach, and ascorbic acid made from such a sorbitol is therefore considered Chometz. An additional concern with the Vitamin C used in tablets is that it may be granulated with lactose (milk sugar) posing a general Kashrus concern, or with cornstarch posing a concern for Pesach. Thiamin (Vitamin B₁), Niacin (Vitamin B₃), Pyridoxine (Vitamin B₆) and Biotin are produced synthetically and pose relatively minor Kashrus concerns. Riboflavin (Vitamin B₂) and Cyanocobalamin (Vitamin B₁₂), on the other hand, are fermentation products and require a reliable Kosher certification. Many serious diseases have been traced to deficiencies of these vitamins in the diet. For example, a neurological disease called beriberi is caused by a deficiency of thiamine. Pellagra, a debilitating illness that was common in the United States in the first part of the last century, was finally traced to a diet deficient in niacin. While whole grains (such as rice and wheat) are rich in these and other vitamins, polished rice and white flour are notoriously deficient. While refined grains may be more appealing, they are certainly not as healthful, and for this reason most flour and rice sold in the United States and many other countries is fortified with niacin, thiamine, and riboflavin. This may indeed be a factor for Sefardim who eat rice on Passover, since although the rice may not pose a problem the vitamin enrichment may since Chometz may have been included in the fermentation process.

The Gemorah (Shabbos 104a) relates that great lessons are to be learned from the juxtaposition of the letters of the Aleph Bais. "Alef Bais" is a mnemonic for "Alef Bina" - which Rashi explains to mean "Learn Torah". "Gimel Daled" symbolizes "Gmol Dalim" - "Be Charitable to the Poor", etc. Each small letter can have a major effect on our spiritual well being, and by ensuring that the A's, B's and C's of our foods are Kosher we can maintain the spiritual well being of the foods we eat.