Putting It Together: Plant Reproduction

Microscopic particles of different shapes and sizes. Some are round while others are oblong.

Figure 1. A micrograph of miscellaneous pollen

As we discussed at the beginning of this module, pollen in the air can cause problems for a lot of people (over 50 million Americans per year, in fact). However, without pollen, a large number of plants wouldn’t be able to reproduce.

For allergy sufferers, the best treatment is to avoid the offending allergens altogether. This may be possible if the allergen is a specific food, like peanuts, which can be cut out of the diet, but not when the very air we breathe is loaded with allergens, such as ragweed pollen. Air purifiers, filters, humidifiers, and conditioners provide varying degrees of relief, but none is 100 percent effective. Various over-the-counter or prescription medications offer relief, too.

  • Antihistamines counter the effects of histamine, the substance that makes eyes water and noses itch and causes sneezing during allergic reactions. Sleepiness was a problem with the first generation of antihistamines, but the newest drugs do not cause such a problem.
  • Nasal steroids are give as anti-inflammatory sprays. They help decrease inflammation, swelling, and mucus production. They work well in combination with antihistamines and, in low doses for brief periods of time, are relatively free of side effects.
  • A nasal spray, cromolyn sodium can help stop hay fever, perhaps by blocking release of histamine and other symptom-producing chemicals. It has few side effects.
  • Available in capsule and spray form, decongestants thin nasal secretions and can reduce swelling and sinus discomfort. Intended for short-term use, they are usually used in combination with antihistamines. Long-term usage of spray decongestants can actually make symptoms worse, while decongestant pills do not have this problem.
  • Immunotherapy (allergy shots) might provide relief for patients who don’t find relief with antihistamines or nasal steroids. They alter the body’s immune response to allergens, thereby helping to prevent allergic reactions. Current immunotherapy treatments are limited because of potential side effects.

Many complementary health approaches have been studied for seasonal allergies. There’s some evidence that a few may be helpful.

  • A 2007 evaluation of six studies of the herb butterbur for seasonal allergies, involving a total of 720 participants, indicated that butterbur may be helpful.
  • Researchers have been investigating probiotics (live microorganisms that may have health benefits) for diseases of the immune system, including allergies. Although some studies have had promising results, the overall evidence on probiotics and seasonal allergies is inconsistent. It’s possible that some types of probiotics might be helpful but that others are not.
  • It’s been thought that eating honey might help to relieve pollen allergies because honey contains small amounts of pollen and might help people build up a tolerance to it. Another possibility is that honey could act as an antihistamine or anti-inflammatory agent. Only a few studies have examined the effects of honey in people with seasonal allergies, and their results have been inconsistent.

Many other natural products have been studied for seasonal allergies, including astragalus, capsaicin, grape seed extract, omega-3 fatty acids, Pycnogenol (French maritime pine bark extract), quercetin, spirulina, stinging nettle, and an herb used in Ayurvedic medicine called tinospora or guduchi. In all instances, the evidence is either inconsistent or too limited to show whether these products are helpful.