Introduction and Historical Perspective
Almost all of us are familiar with hot sauces – who among us hasn’t encountered a bottle of Tabasco, Cholula, Crystal, Tapatío or Sriracha hot sauces at our favorite Mexican Restaurant? Hot sauces represent condiments which are almost universally offered at Mexican and fast food restaurants in the U.S. and elsewhere. Later, I will get into the specific formulations of popular hot sauces, but for now, let it be known that most are mixtures of hot chili peppers, salt and vinegar among other ingredients.
Obviously, the most important component of fiery hot sauces is their chili peppers. All worldwide farmed chili peppers were first grown from wild seeds indigenous to present day Mexico and dated to about 7,000 to 8,500 years before present (B.P.) (1-4). These chili pepper plants were eventually domesticated by about 900 BC (2). Hence, chili peppers were never consumed by humans until our species migrated from Asia to the Americas roughly 15,000 years B.P. Consequently, chili peppers represent a very recent dietary addition for our genus (Homo), which originated at least 2.0 million years ago in Africa. Clearly, numerous North and South American plant foods also represent unique dietary additions for humans as we migrated from Asia to the western hemisphere. So, at least upon initial glance, chili peppers characterize just one of hundreds of novel plant foods that humans encountered as our species made our way into North and South America about 15,000 years B.P.
Nevertheless, chili peppers are nutritionally unique because they are the only plant species in the world which produce capsaicinoids (5, 6). Capsaicinoids are the molecular compounds which give chili peppers their pungent taste and burning sensation when consumed – the higher the capsaicinoids concentration, the greater we perceive the feeling of “heat”. Two major biochemical forms of capsaicinoids exist: capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) and dihydrocapsaicin (8-methyl-N-vanillynonanamide) which represent about 77-98 percent of the capsaicinoids present in chili peppers (7). Other minor capsaicinoids within chili peppers include nordihydrocapsaicin, homocapsaicin, homodihydrocapsaicin and nonivamide among more than 20 similar compounds (7).
All five domesticated species of chili peppers (Capsicum annuum, Capsicum frutenscens, Capsicum chinense, Capsicum pubescens and Capsicum baccatum) originated in the Americas (1-4). On the 15th of January, 1493, during Columbus’ first voyage back to Spain from the new world, he recorded in his diary that large quantities of chili peppers (which he called “axi, ques su piiento”) were harvested on Hispaniola (now the islands of Haiti and the Dominican Republic) by the native Americans (2). Shortly, after his return to Spain from Hispaniola (on the 3d of April, 1493), Columbus presented chili peppers to King Ferdinand and Queen Isabella of Spain who commented that “axi” burned their tongues (2). Diego Alvarez Chanca, a physician on Columbus’ second voyage to the West Indies in 1493-1496 also brought chili peppers back to Spain (8). In the ensuing 200 years, hot chili peppers then rapidly made their way to India, East Asia, and Southeast Asia (2) where they have become integral parts of the cuisines of these regions.
Although only five species of domesticated chili peppers are commonly consumed, numerous cultivars of these species are frequently eaten, and each cultivar maintains widely varying concentrations of capsaicinoids. The “heat” or relative pungency of any species or cultivars of chili peppers is measured by the concentration of capsaicinoids which it contains. These concentrations are most accurately determined by high performance liquid chromatography (HPLC) procedures (9), but most frequently are measured using Scoville Heat Units (SHU), a subjective human measurement of “heat” or spiciness (9). For instance, the cultivar we all know as “green bell peppers” are a member of Capsicum annuum and maintain a Scoville Heat Unit of “0 -100”; meaning that this pepper has little or no perception of spiciness or “heat” (10-39). On the other hand, jalapeno peppers which also belong to the same species, Capsicum annuum, are considerably hotter than green bell peppers and have SHU ratings between 2,500 to 8,000 (10-39). The hottest of all peppers belong to the species, Capsicum chinense (the cultivars of this species are also known as ghost, habanero, datil, Scotch bonnet, naga, fatalli and bhut jolokia among other peppers) and maintain SHU rating between 272,897 and 1,037,305 (10-39). Intermediate to Capsicum annuum and Capsicum chinense chilies are members of the pepper species, Capsicum frutescens, which includes Tabasco, Thai, Piri Piri, Malagueta and Malawian Kambuzi peppers with SHU values ranging from 109,508 to 487,619 (10-39).
The race to produce a “hotter” hot sauce with the highest SHU rating of course makes for an interesting story on the internet, social media, and daily newspapers (40). As hotter hot sauces burn your tongue and make you sweat, few of us consider the health implications of regular capsaicinoid ingestion.
Fiery Hot Sauces: The Good
Table 1 below shows the sodium content, the Scoville Heat Units (SCU), the caloric density, the price and type of peppers found in 33 widely available hot sauces. Note that several hot sauces are manufactured without any added salt, and many brands contain very little sodium (< 35 mg/tsp) including the bestselling McIIhenny’s Tabasco (Original Red) Sauce. Because most hot sauces primarily contain salt, water, vinegar and chili peppers; they are uniformly low in calories (0-10 kcal per teaspoon; Table 1). Accordingly, these two nutritional characteristics (low sodium, low calories) can be viewed as “Good” from a health perspective. The USDA recommended sodium intake is 2,300 mg per day for adults and 1,500 mg per day for people with high blood pressure. Hence, a few hot sauces commonly available at grocery stores (Cholula, Tapatio, Crystal, Franks Red Hot Original and Louisiana Hot Sauce) represent condiments with higher concentrations of salt and therefore should be consumed cautiously for people wanting to reduce their sodium intake.
Table 1. The sodium (Na+) content, Scoville Heat Units, energy (kcal), price and type of chili peppers in 33 brands of hot sauces (10-39).
Many people are unaware that most hot chili pepper sauces are fermented foods. For instance, one of the original hot sauces, McIllhenny’s Tabasco Sauce (Original Red) is produced by grinding fresh peppers into a mash and then soaking the mash in a salt solution inside covered white oak barrels for up to three years (41). The mash is then strained of skins and seeds and mixed with vinegar for a month to produce the final sauce (41). This process (soaking in salt and then vinegar under anerobic [without oxygen] conditions) promotes growth of anaerobic bacteria which allow the food (mashed chili peppers) to ferment but not to spoil and putrefy. Salt encourages the growth of halophilic (salt loving) anaerobic bacteria. Vinegar increases the environmental acidity (lowering the pH) of the mixture which also boosts anaerobic, fermentive, bacterial growth.
Accordingly, the use of salt, vinegar, and covered containers epitomizes a universal and traditional formula to ferment food, thereby preventing its spoilage (42). Hence, fermented plant food contained within covered containers along with salt and vinegar produces a powerful anti-pathogenic effect causing the rapid disappearance of putrefying and disease producing bacteria in the fermented concoction including: Staphylococcus aureus; Salmonella typhymurium; Listeria monocytogenes; Escherichia coli; Clostridium perfringens and Vibrio parahaemolyticus (42, 43).
The anaerobic bacteria and other microorganisms causing the fermentation of vegetables including chili peppers produce metabolic byproducts which are released into the fermented vegetable mixture. Bacteria which ferment plant foods including sauerkraut (fermented cabbage,) pickles (fermented cucumbers,) kimchi (all Korean fermented plant food including cabbage, radishes, cucumbers, chili peppers, mustard leaves, and Welsh onion leaves) (42) encourage further growth of anaerobic bacteria (42, 44). Olives also are fruits produced by their fermentation in salt and vinegar. A less appreciated fermented food is chocolate (the fermented fruit of Theobroma cacao; the South American chocolate tree) which does not require either salt or vinegar for its fermentation.
Many fermented foods contain similar anaerobic bacteria and microorganisms, hence the fermented foods we regularly consume (cheeses, salami, sauerkraut, pickles, olives, kimchi, chili peppers, and chocolate) maintain similar bacterial nutrients derived from the microorganisms and bacteria responsible for their fermentation.
The bacterial compounds infused into fermented foods have seldom been recognized as therapeutic nutritional agents. In part, because nutritionists have not specifically measured these bacterially produced nutrients in fermented foods. For instance, pork has only recently (2016) been demonstrated to be a rich source of short (MK-4) and long chain menaquinones (MK-9 to MK-11) or vitamin K2 (45). Long-chain menaquinones can only enter the human food chain through bacterial contamination (spoilage/fermentation) of the normal fresh food which we eat.
Swine are notorious consumers of rotten, putrid and fermented food (46). Hence it is not surprising that pig tissues should represent a concentrated source of the bacterial nutrients which they consume such as the fat-soluble menaquinones (MK4, MK-9 to MK-11) or vitamin K2. Specifically, long-chain bacterially derived menaquinones are concentrated in the fat tissues of swine (45). A long-term evolutionary function of menaquinones (vitamin K2) is to act as lipid soluble antioxidants for anaerobic bacterial species (47-49).
A wide range of bacterial species have been found with the spontaneous fermentation of Jalapeno chili peppers in a saline environment including the anaerobic lactic acid bacteria (LAB) Lactobacillus plantarum, Leuconostoc citreum, Weissella cibaria and Lactobacillus paraplantarum (50). Further, these same genera (Leuconostoc, Lactobacillus, Weissella) and others Lactococcus and Pediococcus are key players in kimchi fermentation (51).
The crucial point here is not to become overly engaged in the microbiology of specific bacterial species which cause fermentation of chili peppers and other vegetables and fruits, but to realize that common bacterial species are associated with the fermentation of almost all plant foods. These common anaerobic LAB bacterial species, during the fermentation process, synthesize nutrients which have the capacity to serve as lipid soluble antioxidants capable of defusing the toxic ROS produced by the mitochondria in aerobic cells.
Currently, the menaquinone concentrations in bacterial species of LAB are either unknown or obscure; further these lipid soluble antioxidants have rarely or never been measured in fermented chili peppers or other fermented foods except soybeans. Other bacterially produced, important lipid soluble antioxidants which have been shown to improve health such as melatonin (52), pyrroloquinoline quinone (PQQ) (53) and CoQ10 (54) and CoQ9 have not or have barely been measured in fermented foods such as spicy hot sauces, despite the knowledge that fermented peppers and fermented vegetables may contain bacterial species capable of producing these lipid soluble antioxidant compounds.
Numerous studies have suggested that capsaicinoid containing foods may have positive and therapeutic health promoting effects (55-65). In humans, the biological receptor for capsaicin is called the transient receptor potential vanilloid subtype 1 (TRPV1) which is widely expressed in brain, sensory nerves, bladder, gut and blood vessels. TRPV1 is activated by multiple environmental stimuli including exogenous chili pepper capsaicin ingestion, heat, low pH (<5.9) and certain endogenous lipid molecules (63). TRPV1 plays essential roles in inflammation, oxidative stress, and pain sensation (66). Accordingly, capsaicinoids derived from the consumption of hot chili peppers and fiery hot sauces likely have therapeutic functions in the prevention of cardiovascular disease (62-64), diabetes (62, 64), pain (62, 66) and certain autoimmune diseases (65).
Nevertheless, an infrequently recognized downside to consumption of chili peppers is their ability to disrupt the intestinal barrier function (67-78).
Summary (The Good, The Bad)
So, to summarize. Fiery hot sauces are low in calories, frequently (but not always) low in sodium and often contain mashes of chili peppers with bacterially fermented by products and their residues that may have therapeutic health effects together with the beneficial effects of the capsaicinoids present in chili themselves.
Fiery Hot Sauces: The Ugly
Exogenous dietary capsaicinoids from chili peppers represent unique biochemical compounds which the human genome did not encounter until very recently from an evolutionary perspective. As previously demonstrated, Columbus and his crew brought chili peppers to Europe in 1493, and they then spread worldwide in the ensuing 200 years. Accordingly, our species has had little or no time to evolve genetic adaptations to an exogenous plant substance (capsaicinoids) which fundamentally interact with our physiologies via the TRPV1 receptor and other cellular mechanisms.
One of the unexpected health consequences of worldwide chili pepper consumption is its adverse effect upon the human gut, particularly with chili pepper species and cultivars which maintain higher capsaicinoid concentrations and hence higher SHU values. The notion that chili pepper consumption could increase intestinal permeability was unknown until 1994 when Hashimoto and colleagues (67) demonstrated that a vegetable extract only found in sweet peppers (of 32 vegetables analyzed) impaired the intercellular tight junction (TJ) barrier through the paracellular pathway. The authors noted that these changes would, “bring about an invasion of allergenic molecules from the intestinal lumen to the serosal region, which may cause food allergy.” In their 1997 follow-up study (68), Hashimoto and co-workers identified that the active substances in the purified sweet pepper extract which increased intestinal permeability were capsianosides (capsaicins). The authors suggested that, “capsianosides would be useful to enhance the permeability for drugs or other biologically important hydrophilic substances across the intestinal mucosa.”
One year later in 1998 Jensen-Jarolim and colleagues (69) demonstrated that paprika and cayenne pepper spices increased intestinal macromolecular permeability. The authors noted that this event might be of pathophysiological importance, particularly with respect to food allergy and intolerance.
One mechanism underlying capsaicin’s ability to increases intestinal permeability was further examined by Isoda, Han, and colleagues in a series of papers (69-71). These investigators demonstrated that capsaicin’s intestinal permeability impairment resulted partially from capsaicin’s ability to bind the TRPV1 receptor in the gut which directly altered tight junction opening characteristics partially via increasing calcium influx in intestinal cells (70, 71).
One of the implications about capsaicin ingestion from chili peppers is this compound’s ability to promote drug (71), macromolecule and intestinal luminal content (allergens) movement across the intestinal barrier (67-69). A molecule of potential interest from capsaicin’s increase in gut permeability is LPS, a pro-inflammatory residue from gut bacteria. Current studies suggest that capsaicin induces an anti-inflammatory profile that inhibits LPS-induced IL-1β, IL-6 and TNF-α production in a time- and dose-dependent manner (79) that sensitizes the TRPV1 receptor activation (80).
Given this information and the prior data suggesting that capsaicin does not promote autoimmune disease (65), which clearly has an increased gut permeability element, it appears that capsaicin’s ability to increase gut permeability may not be associated with increased inflammation (79) or autoimmunity (65). An important caveat to the autoimmune data associated with capsaicin consumption is a recent study suggesting that hot chili pepper consumption may cause the cellular events leading to disease symptoms in IgA nephropathy patients (81).
Regular consumption of hot chili peppers may have numerous health promoting effects, and its pungent taste adds to the cuisine of worldwide cultures. People trying to lower their sodium intake can choose fiery pepper sauces with lower salt formulations. People with food allergies and certain autoimmune diseases may benefit by limiting pepper sauce consumption or ingesting sauces and chili peppers with lower capsaicin concentrations.
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